Mammalian lysophosphatidic acid acyltransferase

ABSTRACT

Polypeptides are obtained, for example, via expression of encoding cDNA sequences, that have the activity of the enzyme lysophosphatidic acid acyltransferase (LPAAT), also known as 1-acyl sn-glycerol-3-phosphate acyltransferase.

[0001] This is a continuation-in-part of U.S. application serial No. 08/618,651, filed Mar. 19, 1996.

TECHNICAL FIELD OF THE INVENTION

[0002] The present invention provides polypeptides having lysophosphatidic acid acyltransferase (LPAAT) activity and polynucleotides encoding polypeptides having LPAAT activity. The present invention further provides for isolation and production of polypeptides involved in phosphatidic acid metabolism and signaling in mammalian cells, in particular, the production of purified forms of LPAAT.

BACKGROUND OF THE INVENTION

[0003] LPAAT, also referred to as 1-acyl sn-glycerol-3 -phosphate acyltransferase (EC 2.3.1.51), is known to catalyze the acylation of lysophosphatidic acid (LPA) to phosphatidic acid (PA) by acylating the sn-2 position of LPA with a fatty acid acyl-chain moiety. LPA and PA, while originally identified as intermediates in lipid biosynthesis (Kent, Anal Rev. Biochem. 64:315-343, 1995), have more recently been identified as phospholipid signaling molecules that affect a wide range of biological responses (McPhail et al., Proc. Natl. Acad. Sci. USA 92:7931-7935, 1995; Williger et al., J. Biol. Chem. 270:29656-29659, 1995; Moolenaar, Curr. Opin. Cell Biol. 7:203-210, 1995).

[0004] Cellular activation in monocytic and lymphoid cells is associated with rapid upregulation of synthesis of phospholipids (PL) that includes PA, diacylglycerol (DAG) and glycan phosphatidylinositol (PI). PAs are a molecularly diverse group of phospholipid second messengers coupled to cellular activation and mitogenesis (Singer et al., Exp. Opin. Invest. Drugs 3:631-643, 1994). PA can be generated through hydrolysis of phosphatidylcholine (PC) (Exton, Biochim. Biophys. Acta 1212:26-42, 1994) or glycan PI (Eardley et al., Science 251:78-81, 1991; Merida et al., DNA Cell Biol. 12:473-479, 1993), through phosphorylation of DAG by DAG kinase (Kanoh et al., Trends Biochem. Sci. 15:47-50, 1990) or through acylation of LPA at the SN2 position (Bursten et al., Am. J Physiol. 266:C1093-C1104, 1994).

[0005] Compounds that block PA generation and hence diminish lipid biosynthesis and the signal involved in cell activation are therefore of therapeutic interest in, for example, the areas of inflammation and oncology as well as obesity treatment. Therefore, compounds that block LPAAT activity have a similar therapeutic value.

[0006] The genes coding for LPAAT have been isolated in bacteria (Coleman, Mol. Gen. Genet. 232:295-303, 1992), in yeast (Nagiec et al., J. Biol. Chem. 268:22156-22163, 1993) and in plants (Brown et al., Plant Mol. Biol. 26:211-223, 1994; and Hanke et al., Eur J. Biochem. 232:806-810, 1995; Knutzon, et al., Plant Physiol. 109: 999-1006, 1995). Moreover, two human isoforms of LPAAT have been reported (West, et al., DNA Cell Biol. 6: 691-701, 1997). These isoforms are denominated LPAATα and LPAATβ (West, et al., DNA Cell Biol. 6: 691-701, 1997) and are described herein. There remains, however, a need for the isolation of additional mammalian LPAATs, which can be used, for example, to screen for compounds that inhibit LPAAT activity.

SUMMARY OF THE INVENTION

[0007] The present invention provides cDNA sequences, polypeptide sequences, and transformed cells for producing isolated recombinant mammalian LPAAT. The present invention provides four polypeptides corresponding to human LPAAT isoforms. These polypeptides are designated hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ. The invention further provides fragments of these polypeptides which are biologically active, i.e., which retain LPAAT activity. LPAAT activity is defined catalyzing acylation of lysophosphatidic acid (LPA) to phosphatidic acid (PA), specifically by acylating the sn-2 position of LPA with a fatty acid acyl-chain moiety.

[0008] The present invention further provides nucleic acid sequences encoding hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ and polynucleotides coding for biologically active fragments of hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ. The invention further provides “biologically active” polynucleotide fragments, which connotes polynucleotide fragments which encode polypeptides having LPAAT activity. The invention further provides purified LPAATs and antisense oligonucleotides for modulation of expression of the genes coding for LPAAT polypeptides. Assays for screening test compounds for their ability to inhibit LPAATs are also provided.

[0009] The present invention includes the following polynucleotides coding for hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ. The invention provides the DNA sequences of: SEQ ID NO. 1 which encodes for hLPAATα; SEQ ID NO. 7, which encodes hLPAATβ; FIG. 9, which encodes hLPAATγ1 FIG. 10, which encodes hLPAATγ2; and FIG. 11, which encodes and hLPAATδ.

[0010] The invention further includes the polypeptides for hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ, specifically, the amino acid sequences of: SEQ ID NO. 2, which represents hLPAATα; SEQ ID NO. 8, which represents hLPAATβ; FIG. 9, which represents hLPAATγ1; FIG. 10, which represents hLPAATγ2; and FIG. 11, which represents hLPAATδ.

[0011] The invention further comprises biologically active fragments of the amino acid sequences of SEQ ID NO. 2, SEQ ID NO. 8, FIG. 9, FIG. 10, and FIG. 11 or nucleotide fragments of SEQ ID NO. 1, SEQ ID NO. 7, FIG. 9, FIG. 10, and FIG. 11 which encode biologically active LPAAT. The invention further includes polynucleotides which due to the degeneracy of the genetic code encode a polypeptide of SEQ ID NO. 2, SEQ. ID NO. 8, FIG. 9, FIG. 10, and FIG. 11. The invention further includes polynucleotides capable of hybridizing to the nucleic acid sequences of SEQ ID NO. 1, SEQ ID NO. 7, FIG. 9, FIG. 10, and FIG. 11, under high stringency conditions, and which are biologically active.

[0012] Also provided by the present invention are vectors containing a DNA sequence encoding a mammalian LPAAT enzyme in operative association with an expression control sequence. Host cells, transformed with such vectors for use in producing recombinant LPAAT, are also provided with the present invention. The inventive vectors and transformed cells are employed in a process for producing recombinant mammalian LPAAT. In this process, a cell line transformed with a DNA sequence encoding LPAAT in operative association with an expression control sequence, is cultured. The claimed process may employ a number of known cells as host cells for expression of the LPAAT polypeptide, including, for example, mammalian cells, yeast cells, insect cells and bacterial cells. The present invention further provides transformed cells that expresses active mammalian LPAAT.

[0013] The present invention further provides methods for identifying compounds that increase or decrease LPAAT activity, i.e., acylation of LPA to PA. Because PA concentration is involved in numerous cellular pathways, compounds that increase or decrease acylation of LPA to PA are useful in regulating a number of cellular pathways. Such compounds can be used, for example, to augment trilineage hematopoiesis after cytoreductive therapy or to inhibit inflammation following hypoxia and reoxygenation injury (e.g., sepsis, trauma, and ARDS). Moreover, the present invention contemplates the use of such compounds in an in vitro or in vivo context.

[0014] The present invention further includes: An isolated polynucleotide encoding a polypeptide having Lysophosphatidic Acid Acyltransferase (LPAAT) activity, comprising a nucleotide sequence selected from the group consisting of:

[0015] (a) the DNA sequence of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof; and

[0016] (b) a DNA sequence which encodes the polypeptide of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof.

[0017] An isolated polypeptide having LPAAT activity, comprising the amino acid sequence of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof.

[0018] A method for screening one or more compounds to determine whether the one or more compounds increases or decreases LPAAT activity, comprising:

[0019] (a) contacting the polypeptide of the present invention with one or more substrates for the polypeptide and with the one or more compounds; and

[0020] (b) measuring whether the LPAAT activity of the polypeptide is increased or decreased by the one or more compounds.

[0021] A method of expressing the polypeptide of the present invention, comprising:

[0022] (a) introducing into a cell a polynucleotide comprising a nucleotide sequence selected from the group consisting of:

[0023] (i) the DNA sequence of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof; and

[0024] (ii) a DNA sequence which encodes the polypeptide of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof,

[0025] wherein the polynucleotide is operably linked to a promoter; and

[0026] (b) maintaining or growing said cell under conditions that result in the expression of the polypeptide.

[0027] An isolated polynucleotide encoding a polypeptide having Lysophosphatidic Acid Acyltransferase (LPAAT) activity, comprising a DNA sequence capable of hybridizing under high stringency conditions to the complement of the DNA sequences, (a) or (b), described above, and which encodes a polypeptide having LPAAT activity.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 shows the DNA sequence of the cDNA insert of pZplat.11 encoding hLPAATα.

[0029]FIG. 2 shows amino acid sequence alignment of the human LPAATα coding sequence, the yeast LPAAT coding sequence, E. coli LPAAT coding sequence, and the maize LPAAT coding sequence. This comparison shows that human LPAATα has the greatest extended homology with yeast or E. coli LPAAT than with the plant LPAAT.

[0030]FIG. 3 shows the DNA sequence of the cDNA insert pSP.LPAT3 encoding HLPAATβ. The nucleotide sequence analysis and restriction mapping of the cDNA clone revealed a 5′ untranslated region of 39 base pairs and an open reading frame encoding a 278 amino acid polypeptide that spans positions 40-876. It also shows a 3′ untranslated region of 480 base pairs from pSP.LPAT3. The initiation site for translation was localized at nucleotide positions 40-42 and fulfilled the requirement for an adequate initiation site (Kozak, Critical Rev. Biochem. Mol. Biol. 27:385-402, 1992).

[0031]FIG. 4 shows the sequence of the hLPAATβ 278 amino acid open reading frame. The amino acid sequence was used as the query sequence to search for homologous sequences in protein databases. Search of the database based on Genbank Release 92 database from the National Center for Biotechnology Information (NCBI) using the blastp program showed that this protein was most homologous to yeast, bacterial and plant LPAATs.

[0032]FIG. 5 shows amino acid sequences alignment of human LPAATβ coding sequence, human LPAATα coding sequence, yeast LPAAT coding sequence, bacterial (E. coli, H. influenzae, and S. typhimurium) LPAAT coding sequences, and plant (L. douglassi and C. nucifera) LPAAT coding sequences, revealing that the human LPAAT coding sequences have a much more extended homology with the yeast or the bacterial LPAAT than with the plant LPAAT.

[0033]FIG. 6 shows a comparison of LPAAT activity in A549 cells transfected with pCE9.LPAAT1 DNA, or no DNA using a TLC (thin layer chromatography) assay. These data are described in more detail in examples 3 and 4.

[0034]FIGS. 7 and 8 show a comparison of the production of TNF (FIG. 7) and IL-6 (FIG. 8) between A549 cells transfected with pCE9.LPAAT1 and control A549 cells after stimulation with IL-1β and murine TNF. These data show A549 overexpressing LPAAT produces >5 fold more TNF and >10 fold more IL-6 relative to untransfected A549 cells, suggesting that over expression of LPAAT enhances the cytokine signaling response in cells.

[0035]FIG. 9 shows the DNA and the translated sequence of LPAATγ1.

[0036]FIG. 10 shows the DNA and the translated sequence of LPAATγ2.

[0037]FIG. 11 shows the DNA and the translated sequence of LPAATδ.

[0038]FIG. 12 shows the LPAAT amino acid sequence alignment for human LPAAT γ1, γ2, and δ.

[0039]FIG. 13 compares the LPAAT activity in ECV304 cells stably transfected with the expression plasmids for LPAATα (pCE9.LPAAT-α), LPAATβ (pCE9.LPAAT-β) DNA, LPAATγ1 (pC9LPTγ1), LPAATδ (pC2LPTδ), or the control vector (pCE9).

DETAILED DESCRIPTION OF THE INVENTION

[0040] The present invention provides isolated LPAAT polypeptides and isolated polynucleotides encoding LPAAT polypeptides. The term “isolated,” in this context, denotes a polypeptide or polynucleotide essentially free of other polypeptides or nucleic acid sequences, respectively, or of other contaminants normally found in nature.

[0041] The invention includes biologically active LPAAT and biologically active fragments thereof. As used herein, the term “biologically active” in the context of LPAAT activity refers to the ability to catalyze the acylation of lysophosphatidic acid (LPA) to phosphatidic acid (PA) by acylating the sn-2 position of LPA with a fatty acid acyl-chain moiety.

[0042] The term “expression product” as used throughout the specification refers to materials produced by recombinant DNA techniques.

[0043] The present invention contemplates modification of the hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ polypeptide sequences. Such modifications may be deliberate, as by site-directed mutagenesis, or may be spontaneous. All of the polypeptides produced by these modifications are included herein as long as the acyltransferase activity of LPAAT is present.

[0044] For example, the present invention contemplates the deletion of one or more amino acids from the polypeptide sequence of the hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ to create deletion variants. This deletion can be of one or more amino or carboxy terminal amino acids or one or more internal amino acids. The present invention further contemplates one or more amino acid substitutions to the polypeptide sequence of hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAAT to create substitutional variants. The present invention contemplates that such substitutional variants would contain certain functional alterations, such as stabilizing against proteolytic cleavage. Yet, it is understood that such variants retain their acyltransferase activity.

[0045] Substitutions preferably are conservative, that is, one amino acid is replaced with one of similar shape and charge. Conservative substitutions are well known in the art and include, for example, the changes of: alanine to serine; arginine to lysine; asparigine to glutamine or histidine; aspartate to glutamate; cysteine to serine; glutamine to asparigine; glutamate to aspartate; glycine to proline; histidine to asparigine or glutamine; isoleucine to leucine or valine; leucine to valine or isoleucine; lysine to arginine, glutamine, or glutamate; methionine to leucine or isoleucine; phenylalanine to tyrosine, leucine or methionine; serine to threonine; threonine to serine; tryptophan to tyrosine; tyrosine to tryptophan or phenylalanine; and valine to isoleucine or leucine.

[0046] The present invention further contemplates the insertion of one or more amino acids to the polypeptide sequences of hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ to create an insertional variant. Examples of such insertional variants include fusion proteins such as those used to allow rapid purification of the polypeptide and also can include hybrid polypeptides containing sequences from other proteins and polypeptides which are homologues of the inventive polypeptide. For example, an insertional variant could include portions of the amino acid sequence of the polypeptide from one species, together with portions of the homologous polypeptide from another species. Other insertional variants can include those in which additional amino acids are introduced within the coding sequence of the polypeptides. These typically are smaller insertions than the fusion proteins described above and are introduced, for example, to disrupt a protease cleavage site.

[0047] Polypeptides of the present invention can be synthesized by such commonly used methods as t-BOC or FMOC protection of alpha-amino groups. Both methods involve step-wise syntheses whereby a single amino acid is added at each step starting from the C terminus of the peptide (Coligan et al., Current Protocols in Immunology, Wiley Interscience, Unit 9, 1991). In addition, polypeptide of the present invention can also be synthesized by solid phase synthesis methods (e.g., Merrifield, J. Am. Chem. Soc. 85:2149, 1962; and Steward and Young, Solid Phase Peptide Synthesis, Freeman, San Francisco pp. 27-62, 1969) using copolyol (styrene-divinylbenzene) containing 0.1-1.0 mM amines/g polymer. On completion of chemical synthesis, the polypeptides can be deprotected and cleaved from the polymer by treatment with liquid HF 10% anisole for about 15-60 min at 0° C. After evaporation of the reagents, the peptides are extracted from the polymer with 1% acetic acid solution, which is then lyophilized to yield crude material. This can normally be purified by such techniques as gel filtration of Sephadex G-15 using 5% acetic acid as a solvent. Lyophilization of appropriate fractions of the column will yield a homogeneous polypeptide or polypeptide derivatives, which are characterized by such standard techniques as amino acid analysis, thin layer chromatography, high performance liquid chromatography, ultraviolet absorption spectroscopsy, molar rotation, solubility and quantitated by solid phase Edman degradation.

[0048] The invention also provides polynucleotides which encode the hLPAAT polypeptides of the invention. As used herein, “polynucleotide” refers to a polymer of deoxyribonucleotides or ribonucleotides in the form of a separate fragment or as a component of a larger construct.

[0049] Polynucleotide sequences of the invention include DNA, RNA and cDNA sequences. Preferably, the polynucleotide sequences encoding hLPAAT are the sequences of: SEQ ID NO. 1 for hLPAATα; SEQ ID NO. 7 for LPAATβ; FIG. 9 for hLPAATγ1; FIG. 10 for hLPAATγ2; and FIG. 11 for hLPAATδ. DNA sequences of the present invention can be obtained by several methods. For example, the DNA can be isolated using hybridization procedures which are known in the art. Such hybridization procedures include, for example, hybridization of probes to genomic or cDNA libraries to detect shared nucleotide sequences, antibody screening of expression libraries to detect shared structural features, such as a common antigenic epitope, and synthesis by the polymerase chain reaction (PCR).

[0050] Hybridization procedures are useful for screening of recombinant clones by using labeled mixed synthetic oligonucleotide probes, wherein each probe is potentially the complete complement of a specific DNA sequence in a hybridization sample which includes a heterogeneous mixture of denatured double-stranded DNA. For such screening, hybridization is preferably performed on either single-stranded DNA or denatured double-stranded DNA. Hybridization is particularly useful for detection of cDNA clones derived from sources where an extremely low amount of mRNA sequences relating to the polypeptide of interest are present. Using stringent hybridization conditions directed to avoid non-specific binding, it is possible to allow an autoradiographic visualization of a specific cDNA clone by the hybridization of the target DNA to that single probe in the mixture, which is its complement (Wallace et al. Nucl. Acid Res. 9:879, 1981). Stringent conditions preferably include high stringency conditions. See, for example, Maniatis et al, Molecular Cloning (A Laboratory Manual), Cold Spring Harbor Laboratory, pages 387-389, 1982. One such high stringency hybridization condition is, for example, 4×SSC at 65° C., followed by washing in 0.1×SSC at 65° C. for thirty minutes. Alternatively, another high stringency hybridization condition is in 50% formamide, 4×SSC at 42° C.

[0051] The development of specific DNA sequences encoding hLPAAT can also be obtained by isolation of double-stranded DNA sequences from the genomic DNA, chemical manufacture of a DNA sequence to provide the necessary codons for the polypeptide of interest, and in vitro synthesis of a double-stranded DNA sequence by reverse transcription of mRNA isolated for a eukaryotic donor cell. In the latter case, a double-stranded DNA complement of mRNA is eventually formed which is generally referred to as cDNA. Of these three methods for developing specific DNA sequences for use in recombinant procedures, the isolation of genomic DNA isolates is the least common. This is especially true when it is desirable to obtain the microbial expression of mammalian polypeptides due to the presence of introns.

[0052] The synthesis of DNA sequences is frequently a method that is preferred when the entire sequence of amino acids residues of the desired polypeptide product is known. When the entire sequence of amino acid residues of the desired polypeptide is not known, direct synthesis of DNA sequences is not possible and it is desirable to synthesize cDNA sequences. cDNA sequence isolation can be done, for example, by formation of plasmid- or phage-carrying cDNA libraries which are derived from reverse transcription of mRNA. mRNA is abundant in donor cells that have high levels of genetic expression. In the event of lower levels of expression, PCR techniques are preferred. When a significant portion of the amino acid sequence is known, production of labeled single or double stranded DNA or RNA probe sequences duplicating a sequence putatively present in the target cDNA may be employed in DNA/DNA hybridization procedures, carried out on cloned copies of the cDNA (denatured into a single-stranded form) (Jay et al., Nucl. Acid Res. 11:2325, 1983).

[0053] A cDNA expression library, such as lambda gt11, can be screened for hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ polypeptides using antibodies specific for hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ. Such antibodies can be either polyclonally or monoclonally derived.

[0054] The polynucleotides of this invention include sequences that are degenerate as a result of the genetic code. The genetic code is described as degenerate because more than one nucleotide triplet, called a codon, can code for a single amino acid. The present invention contemplates the degeneracy of the genetic code and includes all degenerate nucleotide sequences which encode hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ.

[0055] The present invention also includes polynucleotide sequences complementary to the polynucleotides encoding hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ. Specifically, the present invention includes antisense polynucleotides. An antisense polynucleotide is a DNA or RNA molecule complementary to at least a portion of a specific mRNA molecule (Weintraub, Sci. Amer. 262:40, 1990). The invention embraces all antisense polynucleotides capable of inhibiting the expression of hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, or hLPAATδ. In a cell, the antisense polynucleotides hybridize to the corresponding mRNA, forming a double-stranded molecule. The antisense polynucleotides interfere with the translation of mRNA since the cell cannot translate mRNA that is double-stranded. Antisense oligomers of about 15 nucleotides are preferred, since they are easily synthesized and are less likely to cause problems than larger molecules when introduced into the target of hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, or hLPAATδ-producing cell. The use of antisense methods to inhibit translation of genes is known (e.g., Marcus-Sakura, Anal. Biochem. 172:289, 1988).

[0056] The present invention further includes allelic variations, i.e., naturally-occurring base changes in a species population which may or may not result in an amino acid change, to the polynucleotide sequences encoding hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, or hLPAATδ. The inventive polynucleotide sequences further comprise those sequences which hybridize under high stringency conditions (see, for example, Maniatis et al, Molecular Cloning (A Laboratory Manual), Cold Spring Harbor Laboratory, pages 387-389, 1982) to the coding regions or to the complement of the coding regions of hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, or hLPAATδ. One such high stringency hybridization condition is, for example, 4×SSC at 65° C., followed by washing in 0.1×SSC at 65° C. for thirty minutes. Alternatively, another high stringency hybridization condition is in 50% formamide, 4×SSC at 42° C.

[0057] In addition, ribozyme nucleotide sequences that cleave hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ are included in this invention. Ribozymes are RNA molecules possessing an ability to specifically cleave other single-stranded RNA in a manner analogous to DNA restriction endonucleases. Through the modification of nucleotide sequences which transcribe such RNAs, it is possible to engineer molecules that recognize specific nucleotide sequences in an RNA molecule and cleave it (Cech, J. Amer. Med. Assn. 260:3030, 1988).

[0058] There are two basic types of ribozymes, tetrahymena-type (Hasselhoff, Nature 334:585, 1988) and “hammerhead-type”. Tetrahymena-type ribozymes recognize sequences which are four bases in length, while “hammerhead-type” ribozymes recognize base sequences 11-1.8 bases in length. The longer the recognition sequence, the greater the likelihood that the sequence will occur exclusively in the target mRNA species. Consequently, hammerhead-type ribozymes are preferable to tetrahymena-type ribozymes for inactivating a specific mRNA species.

[0059] Production of Polypeptides

[0060] Polynucleotide sequences encoding hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ polypeptides of the invention can be expressed in either prokaryotes or eukaryotes. Hosts can include microbial (bacterial), yeast, insect and mammalian organisms. Methods of expressing DNA sequences inserted downstream of prokaryotic or viral regulatory sequences in prokaryotes are known in the art (Makrides, Microbio. Rev. 60:512, 1996). Biologically functional viral and plasmid DNA vectors capable of expression and replication in a eukaryotic host are known in the art (Cachianes, Biotechniques 15:255, 1993). Such vectors are used to incorporate DNA sequences of the invention. DNA sequences encoding the inventive polypeptides can be expressed in vitro by DNA transfer into a suitable host using known methods of transfection.

[0061] hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ sequences may be inserted into a recombinant expression vector. The term “recombinant expression vector” refers to a plasmid, virus or other vehicle that has been manipulated by inserting or incorporating genetic sequences. Such expression vectors contain a promoter sequence which facilitates efficient transcription of the inserted genetic sequence of the host. The expression vector typically contains an origin of replication and a promoter, as well as specific genes which allow phenotypic selection of the transformed cells. The DNA segment can be present in the vector, operably linked to regulatory elements, for example, a promoter (e.g., T7, metallothionein I, or polyhedren promoters). Vectors suitable for use in the present invention include, for example, bacterial expression vectors, with bacterial promoter and ribosome binding sites, for expression in bacteria (Gold, Meth. Enzymol. 185:11, 1990), expression vector with animal promoter and enhancer for expression in mammalian cells (Kaufman, Meth. Enzymol. 185:487, 1990) and baculovirus-derived vectors for expression in insect cells (Luckow et al., J. Virol.67:4566, 1993).

[0062] The vector may include a phenotypically selectable marker to identify host cells which contain the expression vector. Examples of markers typically used in prokaryotic expression vectors include antibiotic resistance genes for ampicillin (β-lactamases), tetracycline and chloramphenicol (chloramphenicol acetyltransferase). Examples of such markers typically used in mammalian expression vectors include the gene for adenosine deaminase (ADA), aminoglycoside phosphotransferase (neo, G418), dihydrofolate reductase (DHFR), hygromycin-B-phosphotransferase (HPH), thymidine kinase (TK), and xanthine guanine phosphoriboseyltransferase (XGPRT, gpt).

[0063] In another preferred embodiment, the expression system used is one driven by the baculovirus polyhedrin promoter. The polynucleotide encoding LPAAT can be manipulated by standard techniques in order to facilitate cloning into the baculovirus vector. See Ausubel et al., supra. A preferred baculovirus vector is the pBlueBac vector (Invitrogen, Sorrento, Calif.). The vector carrying a polynucleotide encoding LPAAT is transfected into Spodoptera frugiperda (Sf9) cells by standard protocols, and the cells are cultured and processed to produce the recombinant polypeptide. See Summers et al., A Manual for Methods of Baculovirus Vectors and Insect Cell Culture Procedures, Texas Agricultural Experimental Station.

[0064] The polynucleotides of the present invention can be expressed in any number of different recombinant DNA expression systems to generate large amounts of polypeptide. Included within the present invention are LPAAT polypeptides having native glycosylation sequences, and deglycosylated or unglycosylated polypeptides prepared by the methods described below. Examples of expression systems known to the skilled practitioner in the art include bacteria such as E. coli, yeast such as Pichia pastoris, baculovirus, and mammalian expression systems such as in Cos or CHO cells.

[0065] The polynucleotides of the present invention can be inserted into an expression vector by standard subcloning techniques. In a preferred embodiment, an E. coli expression vector is used which produces the recombinant protein as a fusion protein, allowing rapid affinity purification of the protein. Examples of such fusion protein expression systems are the glutathione S-transferase system (Pharmacia, Piscataway, N.J.), the maltose binding protein system (NEB, Beverley, Mass.), the thiofusion system (Invitrogen, San Diego, Calif.), the Strep-tag II system (Genosys, Woodlands, Tex.), the FLAG system (IBI, New Haven, Conn.), and the 6xHis system (Qiagen, Chatsworth, Calif.). Some of these systems produce recombinant polypeptides bearing only a small number of additional amino acids, which are unlikely to affect the LPAAT ability of the recombinant polypeptide. For example, both the FLAG system and the 6xHis system add only short sequences, both of which are known to be poorly antigenic and which do not adversely affect folding of the polypeptide to its native conformation. Other fusion systems produce proteins where it is desirable to excise the fusion partner from the desired protein. In a preferred embodiment, the fusion partner is linked to the recombinant polypeptide by a peptide sequence containing a specific recognition sequence for a protease. Examples of suitable sequences are those recognized by the Tobacco Etch Virus protease (Life Technologies, Gaithersburg, Md.) or Factor Xa (New England Biolabs, Beverley, Mass.) or enterokinase (Invitrogen, San Diego, Calif.).

[0066] In an embodiment of the present invention, the polynucleotides encoding LPAAT are analyzed to detect putative transmembrane sequences. Such sequences are typically very hydrophobic and are readily detected by the use of standard sequence analysis software, such as MacDNASIS (Hitachi, San Bruno, Calif.). The presence of transmembrane sequences is often deleterious when a recombinant protein is synthesized in many expression systems, especially in E. coli, as it leads to the production of insoluble aggregates which are difficult to renature into the native conformation of the polypeptide.

[0067] Accordingly, deletion of one or more of the transmembrane sequences may be desirable. Deletion of transmembrane sequences typically does not significantly alter the conformation or activity of the remaining polypeptide structure. However, one can determine whether deletion of one or more of the transmembrane sequences has effected the biological activity of the LPAAT protein by, for example, assaying the activity of the LPAAT protein containing one or more deleted sequences and comparing this activity to that of unmodified LPAAT. Assaying LPAAT activity can be accomplished by, for example, contacting the LPAAT protein of interest with the substrates LPA and fatty acyl-CoA and measuring the generation of PA or CoA, or, alternatively, measuring the formation of free CoA. Such assays for determining LPAAT activity are described in more detail below in the section describing screening assays.

[0068] Moreover, transmembrane sequences, being by definition embedded within a membrane, are inaccessible as antigenic determinants to a host immune system. Antibodies to these sequences will not, therefore, provide immunity to the host and, hence, little is lost in terms of generating monoclonal or polyclonal antibodies by omitting such sequences from the recombinant polypeptides of the invention. Deletion of transmembrane-encoding sequences from the polynucleotide used for expression can be achieved by standard techniques. See Ausubel et al., supra, Chapter 8. For example, fortuitously-placed restriction enzyme sites can be used to excise the desired gene fragment, or the PCR can be used to amplify only the desired part of the gene.

[0069] Transformation of a host cell with recombinant DNA may be carried out by conventional techniques. When the host is prokaryotic, such as E. coli, competent cells which are capable of DNA uptake can be prepared from cells harvested after exponential growth phases and subsequently treated by a CaCl₂ method using standard procedures. Alternatively, MgCl₂ or RbCl can be used. Transformation can also be performed after fonning a protoplast of the host cell or by electroporation.

[0070] When the host is a eukaryote, methods of transfection of DNA, such as calcium phosphate co-precipitates, conventional mechanical procedures, (e.g., microinjection), electroporation, liposome-encased plasmids, or virus vectors may be used. Eukaryotic cells can also be cotransformed with DNA sequences encoding hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ polypeptides of the invention, and a second foreign DNA molecule encoding a selectable phenotype, such as the herpes simplex thymidine kinase gene. Another method uses a eukaryotic viral vector, such as simian virus 40 (SV40) or bovine papilloma virus to transiently infect or transform eukaryotic cells and express the hLPAATα, HLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ polypeptides.

[0071] Expression vectors that are suitable for production of LPAAT polypeptides preferably contain (1) prokaryotic DNA elements coding for a bacterial replication origin and an antibiotic resistance marker to provide for the growth and selection of the expression vector in a bacterial host; (2) eukaryotic DNA elements that control initiation of transcription, such as a promoter; and (3) DNA elements that control the processing of transcripts, such as a transcription termination/polyadenylation sequence. LPAAT polypeptides of the present invention preferably are expressed in eukaryotic cells, such as mammalian, insect and yeast cells. Mammalian cells are especially preferred eukaryotic hosts because mammalian cells provide suitable post-translational modifications such as glycosylation. Examples of mammalian host cells include Chinese hamster ovary cells (CHO-K1; ATCC CCL61), rat pituitary cells (GH₁; ATCC CCL82), HeLa S3 cells (ATCC CCL2.2), rat hepatoma cells (H-4-II-E; ATCC CRL1548) SV40-transformed monkey kidney cells (COS-1; ATCC CRL 1650) and murine embryonic cells (NIH-3T3; ATCC CRL 1658). For a mammalian host, the transcriptional and translational regulatory signals may be derived from viral sources, such as adenovirus, bovine papilloma virus, simian virus, or the like, in which the regulatory signals are associated with a particular gene which has a high level of expression. Suitable transcriptional and translational regulatory sequences also can be obtained from mammalian genes, such as actin, collagen, myosin, and metallothionein genes.

[0072] Transcriptional regulatory sequences include a promoter region sufficient to direct the initiation of RNA synthesis. Suitable eukaryotic promoters include the promoter of the mouse metallothionein I gene (Hamer et al., J. Molec. Appl. Genet. 1:273,1982); the TK promoter of Herpes virus (McKnight, Cell 31: 355, 1982); the SV40 early promoter (Benoist et al., Nature 290:304, 1981); the Rous sarcoma virus promoter (Gorman et al., Proc. Nat'l. Acad. Sci. USA 79:6777, 1982); and the cytomegalovirus promoter (Foecking et al., Gene 45:101, 1980). Alternatively, aprokaryotic promoter, such as the bacteriophage T3 RNA polymerase promoter, can be used to control fusion gene expression if the prokaryotic promoter is regulated by a eukaryotic promoter (Zhou et al., Mol. Cell. Biol. 10:4529, 1990; Kaufman et al., Nucl. Acids Res. 19:4485, 1991).

[0073] An expression vector can be introduced into host cells using a variety of techniques including calcium phosphate transfection, liposome-mediated transfection, electroporation, and the like. Preferably, transfected cells are selected and propagated wherein the expression vector is stably integrated in the host cell genome to produce stable transfornants. Techniques for introducing vectors into eukaryotic cells and techniques for selecting stable transformants using a dominant selectable marker are described, for example, by Ausubel and by Murray (ed.), Gene Transfer and Expression Protocols (Humana Press 1991). Examples of mammalian host cells include COS, BHK, 293 and CHO cells.

[0074] Purification of Recombinant Polypeptides

[0075] The LPAAT polypeptide expressed in any of a number of different recombinant DNA expression systems can be obtained in large amounts and tested for biological activity. The recombinant bacterial cells, for example E. coli, are grown in any of a number of suitable media, for example LB, and the expression of the recombinant polypeptide induced by adding IPTG to the media or switching incubation to a higher temperature. After culturing the bacteria for a further period of between 2 and 24 hours, the cells are collected by centrifugation and washed to remove residual media. The bacterial cells are then lysed, for example, by disruption in a cell homogenizer and centrifuged to separate the dense inclusion bodies and cell membranes from the soluble cell components. This centrifugation can be performed under conditions whereby the dense inclusion bodies are selectively enriched by incorporation of sugars such as sucrose into the buffer and centrifugation at a selective speed. If the recombinant polypeptide is expressed in the inclusion, these can be washed in any of several solutions to remove some of the contaminating host proteins, then solubilized in solutions containing high concentrations of urea (e.g. 8 M) or chaotropic agents such as guanidine hydrochloride in the presence of reducing agents such as β-mercaptoethanol or DTT (dithiothreitol). At this stage it may be advantageous to incubate the polypeptide for several hours under conditions suitable for the polypeptide to undergo a refolding process into a conformation which more closely resembles that of the native polypeptide. Such conditions generally include low polypeptide (concentrations less than 500 mg/ml), low levels of reducing agent, concentrations of urea less than 2 M and often the presence of reagents such as a mixture of reduced and oxidized glutathione which facilitate the interchange of disulphide bonds within the protein molecule. The refolding process can be monitored, for example, by SDS-PAGE or with antibodies which are specific for the native molecule. Following refolding, the polypeptide can then be purified further and separated from the refolding mixture by chromatography on any of several supports including ion exchange resins, gel permeation resins or on a variety of affinity columns.

[0076] Isolation and purification of host cell expressed polypeptide, or fragments thereof may be carried out by conventional means including, but not limited to, preparative chromatography and immunological separations involving monoclonal or polyclonal antibodies.

[0077] These polypeptides may be produced in a variety of ways, including via recombinant DNA techniques, to enable large scale production of pure, biologically active hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ useful for screening compounds for, e.g., trilineage hematopoietic and anti-inflammatory therapeutic applications, and developing antibodies for therapeutic, diagnostic and research use.

[0078] Screening Assays

[0079] The hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ polypeptides of the present invention are also useful in a screening methodology for identifying compounds or compositions which affect cellular signaling of an inflammatory response. Such compounds or compositions to be tested can be selected from a combinatorial chemical library or any other suitable source (Hogan, Jr., Nat. Biotechnology 15:328, 1997).

[0080] This method comprises, for example, contacting hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and/or hLPAATδ in the presence of compound and substrate for LPAAT, namely LPA and fatty acyl-CoA. These hLPAAT proteins can either be purified prior to incubation or can be contained in extracts from a cell line or cell lines (for example, Sf9, ECV304, A549) transfected with cDNA encoding these polypeptides (West et al., DNA Cell Biol. 16.691, 1997). Alternatively, hLPAAT protein can be purified from transfected cells, and the protein, being a transmembrane protein, can then be reconstituted in a lipid bilayer to form liposomes for delivery into cells (Weiner, Immunomethods 4:201, 1994).

[0081] The effect of a compound or composition on hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, or hLPAATδ activity can be determined, for example, by measuring the generation of PA and CoA. PA can be measured by, for example, TLC methods described in Examples 3 and 7, found below. Alternatively, LPAAT activity can be assayed by detecting the formation of free CoA in reaction. CoA, which contains a free sulfhydryl-group, can be measured either by, for example, colorimetric or fluorescenic methods with sulfhydryl-specific reagents, such as, 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) or ThioGlo (Covalent Associates, Woburn, Mass.). The observed effect on hLPAATα, hLPAATβ, hLPAATγ1, hLPAATγ2, and hLPAATδ may be either inhibitory or stimulatory.

[0082] Peptide Sequencing

[0083] Purified polypeptides prepared by the methods described above can be sequenced using methods well known in the art, for example using a gas phase peptide sequencer (Applied Biosystems, Foster City, Calif.). Because the proteins of the present invention may be glycosylated, it is preferred that the carbohydrate groups are removed from the proteins prior to sequencing. This can be achieved by using glycosidase enzymes. Preferably, glycosidase F (Boehringer-Mannheim, Indianapolis, Ind.) is used. To determine as much of the polypeptide sequence as possible, it is preferred that the polypeptides of the present invention be cleaved into smaller fragments more suitable for gas-phase sequence analysis. This can be achieved by treatment of the polypeptides with selective peptidases, and in a particularly preferred embodiment, with endoproteinase lys-C (Boehringer). The fragments so produced can be separated by reversed-phase HPLC chromatography.

[0084] Antibodies Directed to LPAAT

[0085] Antibodies to human LPAAT can be obtained using the product of an LPAAT expression vector or synthetic peptides derived from the LPAAT coding sequence coupled to a carrier (Pasnett et al., J. Biol. Chem. 263:1728, 1988) as an antigen. The preparation of polyclonal antibodies is well-known to those of skill in the art. See, for example, Green et al., “Production of Polyclonal Antisera,” in Immunochemical Protocols (Manson, ed.), pages 1-5 (Humana Press 1992). Alternatively, an LPAAT antibody of the present invention may be derived from a rodent monoclonal antibody (MAb). Rodent monoclonal antibodies to specific antigens may be obtained by methods known to those skilled in the art. See, for example, Kohler and Milstein, Nature 256:495, 1975, and Coligan et al. (eds.), Current Protocols in Immunology, 1:2.5.1-2.6.7 (John Wiley & Sons 1991). Briefly, monoclonal antibodies can be obtained by injecting mice with a composition comprising an antigen, verifying the presence of antibody production by removing a serum sample, removing the spleen to obtain B-lymphocytes, fusing the B-lymphocytes with myeloma cells to produce hybridomas, cloning the hybridomas, selecting positive clones which produce antibodies to the antigen, culturing the clones that produce antibodies to the antigen, and isolating the antibodies from the hybridoma cultures.

[0086] MAbs can be isolated and purified from hybridoma cultures by a variety of well-established techniques. Such isolation techniques include affinity chromatography with Protein-A Sepharose, size-exclusion chromatography, and ion-exchange chromatography. See, for example, Coligan at pages 2.7.1-2.7.12 and pages 2.9.1-2.9.3. Also, see Baines et al., “Purification of Immunoglobulin G (IgG),” in Methods in Molecular Biology, 10:79-104 Humana Press, Inc. 1992. An LPAAT antibody of the present invention may also be derived from a subhuman primate antibody. General techniques for raising therapeutically useful antibodies in baboons may be found, for example, in Goldenberg et al., international patent publication No. WO 91/11465 (1991), and in Losman et al., Int. J. Cancer 46:310, 1990.

[0087] Alternatively, a therapeutically useful LPAAT antibody may be derived from a “humanized” monoclonal antibody. Humanized monoclonal antibodies are produced by transferring mouse complementary determining regions from heavy and light variable chains of the mouse immunoglobulin into a human variable domain, and then, substituting human residues in the framework regions of the murine counterparts. The use of antibody components derived from humanized monoclonal antibodies obviates potential problems associated with the immunogenicity of murine constant regions. General techniques for cloning murine immunoglobulin variable domains are described, for example, by the publication of Orlandi et al., Proc. Nat'l. Acad. Sci. USA 86:3833, 1989. Techniques for producing humanized MAbs are described, for example, by Jones et al., Nature 321:522, 1986, Riechmann et al., Nature 332:323, 1988, Verhoeyen et al., Science 239:1534, 1988, Carter et al., Proc. Nat'l Acad. Sci. USA 89:4285, 1992, Sandhu, Crit. Rev. Biotech. 12: 437, 1992, and Singer et al., J. Immun. 150:2844, 1993, each of which is hereby incorporated by reference.

[0088] As an alternative, an LPAAT antibody of the present invention may be derived from human antibody fragments isolated from a combinatorial immunoglobulin library. See, for example, Barbas et al., METHODS. A Companion to Methods in Enzymology 2:119 1991, and Winter et al., Ann. Rev. Immunol. 12:433, 1994, which are incorporated by reference. Cloning and expression vectors that are useful for producing a human immunoglobulin phage library can be obtained, for example, from STRATAGENE Cloning Systems (La Jolla, Calif.). In addition, an LPAAT antibody of the present invention may be derived from a human monoclonal antibody. Such antibodies are obtained from transgenic mice that have been “engineered” to produce specific human antibodies in response to antigenic challenge. In this technique, elements of the human heavy and light chain locus are introduced into strains of mice derived from embryonic stem cell lines that contain targeted disruptions of the endogenous heavy chain and light chain loci. The transgenic mice can synthesize human antibodies specific for human antigens, and the mice can be used to produce human antibody-secreting hybridomas. Methods for obtaining human antibodies from transgenic mice are described by Green et al., Nature Genet. 7:13, 1994; Lonberg et al., Nature 368:856, 1994, and Taylor et al., Int. Immun. 6:579, 1994.

[0089] hLPAATα and hLPAATβ

[0090] hLPAATα

[0091] Search of the Genbank database of expressed sequence tag (dbest) using either the yeast or plant LPAAT protein sequences as probe came up with several short stretches of cDNA sequences with homology to the yeast or plant LPAAT protein sequence. These cDNA sequences of interest were derived from single-run partial sequencing of random human cDNA clones projects carried out by either the WashU-Merck EST or the Genexpress-Genethon program. An example of the amino acids sequence homology between the yeast LPAAT and a human cDNA clone (dbest#102250) is shown below by comparing SEQ ID NO. 3 (top amino acid sequence) with SEQ ID NO 4 (bottom amino acid sequence):

[0092] PFKKGAFHLAQQGKIPIVPVVVSNTSTLVSPKYGVFNRGCMIVRILKPISTE

[0093] * ****** * **** * * * * * ** * * **

[0094] PSNCGAFHLAVQAQVPIVPIVMSSYQDFYCKKERRFTSGQCQVRVLPPVPTE

[0095] The top line refers to the yeast LPAAT sequence from amino acids 169 to 220 and the bottom line refers to the homologous region from the dbest clone#102250. Identical amino acids between these two sequences are shown in block letters with asterisks in between

[0096] Accordingly, a synthetic oligonucleotide (o.BLPAT.2R), 5′-TGCAAGATGGAAGGCGCC-3′ (SEQ ID NO. 5), was made based on the complement sequence of the conserved amino acids region, GAFHLA (SEQ ID NO. 6), of clone#102250. o.BPLAT.2R was radiolabeled at its 5′-end using γ-³²P-ATP and T4 polynucleotide kinase as a probe in screening a λzap human brain cDNA library (Stratagene).

[0097] Screening of the cDNA library was accomplished by filter hybridization using standard methods (Current Protocols in Molecular Biology, John Wiley & Sons, Inc., 1995). Duplicate filters containing DNA derived from λ phage plagues were prehybridized at 60° C. for 2 hr in 6×SSC (1×SSC is 0.15 M NaCl, 0.015 M sodium citrate, pH 7.0), 5×Denhardt's solution (1×Denhardt's solution is 0.02% Ficoll, 0.02% bovine serum albumin, and 0.02% polyvinyl-pyrrolidone), 0.1% sodium dodecyl sulfate (SDS), 50 mg/ml sonicated and denatured salmon sperm DNA. Hybridization was carried out in the same buffer as used for prehybridzation. After hybridization, the filters were washed in 6×SSC at 42° C., and autoradiographed.

[0098] Of the approximately 1×10⁶ clones from the human brain cDNA library that were screened, twelve clones were identified that hybridized with the probe in duplicate filters. Eleven out twelve clones were enriched and recovered after a secondary screen. Ten enriched phage samples were then converted to plasmid transformed cells by co-infecting E. coli XL1-Blue with the helper phage R408 using Stratagene's recommended procedure. Colony filter hybridization was performed and identified those colonies that “lit up” with the probe. Seven out of the ten pools of colonies contained positive clones. Two out of these seven clones, pZlpat.10 and pZlpat.11, contained inserts >2 kb. Restriction mapping using a combination of Sst I, Pst I and BamHI digests showed these two clones contained many common fragments with respect to each other.

[0099] Nucleotide sequencing of the cDNA inserts in pZlpat.10 and pZlpat.11 was performed. FIG. 1 shows the DNA sequence of the cDNA insert of pZplat.11. The nucleotide sequence analysis and restriction mapping of the cDNA clone revealed a 5′-untranslated region of >300 bp, an open reading frame capable of encoding a 283 amino acid polypeptide, and a 3′-untranslated region of >800 bp. The initiation site for translation was localized at nucleotide positions 319-321 and fulfilled the requirement for an adequate initiation site according to Kozak (Kozak, Critical Rev. Biochem. Mol. Biol. 27:385-402, 1992). There was another upstream ATG at positions 131-133 with an in-phase stop codon at positions 176-178. Except with a shorter 5′-untranslated region, the cDNA insert of pZplat.10 has the same DNA sequence as that of pZplat.11.

[0100] The sequence of the 283 amino acid open reading frame in pZplat.11 was used as the query sequence to search for homologous sequences in protein databases. Search of the database based on Genbank Release 90 from the National Center for Biotechnology Information (NCBI) using the blastp program showed that the protein encoded by pZplat.11 was most homologous to the yeast and bacterial LPAATs. FIG. 2 shows amino acid sequences alignment of the putative human LPAATα coding sequence, the yeast LPAAT coding sequence, the E. coli LPAAT coding sequence, and the maize LPAAT coding sequence, revealing that human LPAATα has a much more extended homology with the yeast or the E. coli LPAAT than with the plant LPAAT.

[0101] hLPAATβ

[0102] Search of the Genbank database (Boguski, et al., Science 265:1993-1994, 1994) of expressed sequence tag (dbEST) using either the yeast or plant LPAAT protein sequences as probe came up with several short stretches of cDNA sequences with homology to the yeast or plant LPAAT protein sequence. These cDNA sequences of interest were derived from single-run partial sequencing of random human cDNA clones projects carried out mainly by I.M.A.G.E. Consortium [LLNL] cDNA clones program. An example of the amino acids sequence homology between the yeast LPAAT and a human cDNA clone (dbEST#363498) is shown below: 180       190       200       210       220       230 QQGKIPIVPVVVSNTSTLVSPKYGVFNRGCMIVRILKPISTENLTKDKIGEFAEKVRDQM VRENVPIVPVVYSSFSSFYNTKKKFFTSGTVTVQVLEAIPTSGLTAADVPALRGTPATGP          70        80        90       100       110 120

[0103] The top line refers to the yeast LPAAT sequence from amino acids 171 to 230 (SEQ ID NO. 9) and the bottom line refers to the homologous region from the dbest clone#363498 using the +1 reading frame (SEQ ID NO. 10). Identical and conserved amino acids between these two sequences are shown with double dots and single dot, respectively, in between. In order to find out if such cDNA clones with limited homology to yeast LPAAT sequence indeed encode human LPAATβ sequence, it was necessary to isolate the full-length cDNA clone, insert it into an expression vector, and to test if cells transformed or transfected with the cDNA expression vector produced more LPAAT activity.

[0104] Accordingly, two synthetic oligonucleotides, 5′-CCTCAAAGTG TGGATCTATC-3′ (o.LPAT3.F) (SEQ ID NO. 11) and 5′-GGAAGAGTAC ACCACGGGGA C-3′ (o.LPAT3.R), (SEQ ID NO. 12) were ordered (Life Technologies, Gaithersburg, Md.) based on, respectively, the coding and the complement sequence of clone#363498. o.LPAT3.R was used in combination with a forward vector primer (o.sport.1), 5′-GACTCTAGCC TAGGCTTTTG C-3′ (SEQ ID NO. 13) for amplification of the 5′-region, while o.LPAT3.F was used in combination with a reverse vector primer (o.sport.1R), 5′-CTAGCTTATA ATACGACTCA C-3′ (SEQ ID NO. 14), for amplification of the 3′-region of potential LPAATβ sequences from a pCMV.SPORT human leukocyte cDNA library (Life Technologies, Gaithersburg, Md.). A 700 bp PCR fragment derived from o.sport.1 and o.LPAT3.R amplification was cut with EcoR I before inserting in between the Sma I and EcoR I of pBluescript(II)SK(−) (Stratagene, LaJolla, Calif.) to generate pLPAT3.5′. A 900 bp PCR fragment derived from o.sport.1R and o.LPAT3.F amplification was cut with Xba I before inserting in between the Sma I and Xba I of pBluescript(II)SK(−) (Stratagene, LaJolla, Calif.) to generate pLPAT3.3′. Nucleotide sequencing analysis of the cDNA inserts from these two plasmids showed they contained overlapping sequences with each other, sequences that matched with the dbEST#363498 as well as extensive homology with the yeast LPAAT amino acids sequence (Nagiec et al., J. Biol. Chem. 268:22156-22163, 1993). To assemble the two halves of the cDNA into a full-length clone, the 560 bp Nco I-Nar I fragment from pLPAT3.5′ and the 780 bp Nar I-Xba I fragment from pLPAT3.3′ were inserted into the Nco I/Xba I vector prepared from pSP-luc+ (Promega, Madison, Wis.) via a three-part ligation to generate pSP.LPAT3.

[0105]FIG. 3 shows the DNA sequence ID of the cDNA insert of pSP.LPAT3. The nucleotide sequence analysis and restriction mapping of the cDNA clone revealed a 5′-untranslated region of 39 bp, an open reading frame capable of encoding a 278 amino acids polypeptide that spans nucleotide positions 40 to 876 and a 3′-untranslated region of 480 bp (FIG. 3). The initiation site for translation was localized at nucleotide positions 40-42 and fulfilled the requirement for an adequate initiation site according to Kozak (Kozak, Critical Rev. Biochem. Mol. Biol. 27:385-402, 1992).

[0106] The sequence of the 278 amino acid open reading frame (FIG. 4) was used as the query sequence to search for homologous sequences in protein databases. Search of the database based on Genbank Release 92 from the National Center for Biotechnology Information (NCBI) using the blastp program showed that this protein was most homologous to the yeast, bacterial and plant LPAATs. FIG. 5 shows amino acid sequences alignment of this putative human LPAATβ coding sequence, human LPAATα coding, the yeast LPAAT coding sequence, the bacterial (E. coli, H. influenzae, and S. typhimurium) LPAAT coding sequences, and the plant (L. douglassi and C. nucifera) LPAAT coding sequences, revealing that the human LPAAT coding sequences have a much more extended homology with the yeast or the bacterial LPAAT than with the plant LPAAT.

[0107] hLPAATγ1, hLPAATγ2, or hLPAATδ

[0108] Described below is the isolation of human LPAAT isoforms hLPAATγ1, hLPAATγ2, or hLPAATδ, which are distinct from hLPAATα and hLPAATβ.

[0109] Search of the Genbank database (Boguski, et al., Science 265:1993-1994, 1994) of expressed sequence tag (dbEST) using the maize form-I LPAAT protein (Brown, et al., Plant Mol. Biol. 26: 211-223, 1994) sequences as probes resulted in the identification of several short stretches of human cDNA sequences with homology to the maize LPAAT protein sequence. These cDNA sequences of interest were derived from single-run partial sequencing of random human cDNA clones projects carried out mainly by I.M.A.G.E. Consortium [LLNL] cDNA clones program. An example of the amino acids sequence homology between the maize LPAAT and a human cDNA clone (GenBank#T55627) is shown below: 150 GLQRLKDFPRPFWLALFVEGTRF 172     ::.::.:.:  .:. :. :::::     GLRRLSDYPEYMWFLIJYCEGTRF

[0110] The top line refers to the maize LPAAT sequence from amino acids 150 to 172 and the bottom line refers to the homologous region from the dbEST clone with GenBank#T55627. Identical and conserved amino acids between these two sequences are shown as double dots and single dots, respectively, in the row in between. In order to determine if these human cDNA clones with homology to maize LPAAT but distinct from human LPAATα or LPAATβ indeed encoded human LPAAT, it was undertaken to isolate the full-length cDNA clone, insert it into an expression vector, and to test if cells transformed or transfected with the cDNA expression vector produced more LPAAT activity.

[0111] Accordingly, a synthetic oligonucleotides, 5′-GACTACCCC GAGTACATG TGGTTTCTC-3′ (oLPTg_(—)1F) was ordered (Life Technologies, Gaithersburg, Md.) based on the coding region corresponding to amino acids DYPEYMWFL of clone GenBank#T55627. oLPTg_(—)1F was used in combination with a reverse vector primer (o.sport.1R), 5′-CTAGCTTATA ATACGACTCA C-3′, for amplification of the 3′-region of potential LPAAT sequences from a pCMV.SPORT human leukocyte cDNA library (Life Technologies, Gaithersburg, Md.). A 1,000 bp PCR fragment derived from o.sport.1R and oLPTg_(—)1F amplification was cut with Xho I before inserting in between the Sma I and Xho I of pBluescript(II)SK(−) (Stratagene, LaJolla, Calif.) to generate the plasmid pLPTγ_(—)3′. Nucleotide sequencing (performed by the Seattle Biomedical Research Institute sequencing service) analysis of the cDNA inserts from plasmid pLPTg_(—)3′showed it contained sequences that matched with the clone GenBank#T55627 as well as extensive homology with the C-terminal end of the maize LPAAT amino acids sequence (Brown, et al., Plant Mol. Biol. 26: 211-223, 1994). To isolate the 5′-portion of this putative LPAAT clone, a synthetic oligonucleotide, 5′-CACATGTCCG CCTCGTACTT CTTC-3′ (oLPTg_(—)1R), complementary to a region just downstream of the Bam HI site of the cDNA within generate the plasmid pLPTg_(—)3′ was used in combination with a forward vector primer (o.sport.1), 5′-GACTCTAGCC TAGGCTTTTG C-3′ for amplification of the 5′-region from a pCMV.SPORT human leukocyte cDNA library (Life Technologies, Gaithersburg, Md.). The PCR fragments generated were cut with Acc65 I and BamH I before inserting in between the Acc65 I and BamH I of pBluescript(II)SK(−) (Stratagene, LaJolla, Calif.). DNA sequence analysis of two cDNA clones containing, respectively, a 980 bp and a 770 bp Acc65 I-BamH I inserts showed they contained sequences that overlapped with the cDNA insert of pLPTγ_(—)3′as well as extensive homology with the N-terminal end of the maize LPAAT amino acids sequence. The DNA sequence of these two cDNA clones diverged at the 5′-regions, suggesting the presence of two alternatively spliced variants with one variant (pLPγ1_(—)5′) containing an additional 62 amino acids at the N-terminus relative to the other one (pLPγ2_(—)5′). To assemble the two halves of each cDNA into full-length clones, the 980 bp Acc65 I-BamnH I fragment from pLPγ1_(—)5′or the 770 bp Acc65 I-BamiH I fragment from pLPγ2_(—)5′ were inserted into the Acc65 I/Xho I vector prepared from pBluescript(II)SK(−) (Stratagene, LaJolla, Calif.) along with the 870 bp Barn HI-Xho I fragment from pLPTγ_(—)3′via a three-part ligation to generate pSK_LPγ1 and pSK_LPγ2, respectively.

[0112]FIG. 9 shows the DNA and the translated sequence (LPAAT-γ1) of the cDNA insert of pSK_LPγ1. The nucleotide sequence analysis and restriction mapping of the cDNA clone revealed a 5′-untranslated region of 183 bp with two ATGs and an in-phase stop codon, an open reading frame capable of encoding a 376 amino acids polypeptide that spans nucleotide positions 184 to 1314 and a 3′-untranslated region of 345 bp. The initiation site for translation was localized at nucleotide positions 184-186 and fulfilled the requirement for an adequate initiation site (Kozak, Critical Rev. Biochem. Mol. Biol. 27:385-402, 1992).

[0113]FIG. 10 shows the DNA and the translated sequence (hLPAATγ2) of the cDNA insert of pSK_LPγ2. The nucleotide sequence analysis and restriction mapping of the cDNA clone revealed a 5′-untranslated region of 232 bp with two upstream ATGs with in-phase stop codons, an open reading frame capable of encoding a 314 amino acids polypeptide that spans nucleotide positions 133 to 1177 and a 3′-untranslated region of 346 bp. The initiation site for translation was localized at nucleotide positions 233-235 and fulfilled the requirement for an adequate initiation site (Kozak, Critical Rev. Biochem. Mol. Biol. 27:385-402, 1992).

[0114] The sequence of the 376 amino acid open reading frame of hLPAATγ1 (FIG. 9) was used as the query sequence to search for homologous sequences in protein databases. Search of the Genbank database from the National Center for Biotechnology Information (NCBI) using the tblastn program showed that this protein was distinct but homologous to a human EST sequence with GenBank #H18562. Shown below is the amino acid sequences alignment of LPAAT-γ1 with this putative human LPAAT coding sequence (LPAAT-δ): LPAAT-γ1 MGLLAFLKTQFVLHLLVGFVFVVSGLVINFVQLCTLALWPVSKQLY 46 : :   ::.::. ::.  .::. :::.:: .:: :: :::. :::. LPAAT-δ MDLAGLLKSQFLCHLVFCYVFIASGLIINTTQLFTLLLWPINKQLF 340

[0115] The top line refers to the human LPAAT-γ1 sequence from amino acids 1 to 46 and the bottom line refers to the homologous region from the dbEST clone with GenBank #H18562. Identical and conserved amino acids between these two sequences are shown as double dots and single dots, respectively, in the row in between. The cDNA for this putative LPAAT-δ clone (Genome Systems Inc., St. Louis, Mo.) was isolated for further analysis.

[0116]FIG. 11 shows the DNA and the translated sequence (LPAAT-δ) of this cDNA insert. Nucleotide sequence analysis and restriction mapping revealed a 5′-untranslated region of 157 bp with an upstream ATG and stop codons in all three reading frames, an open reading frame capable of encoding a 378 amino acids polypeptide that spans nucleotide positions 158 to 1294 and a 3′-untranslated region of 480 bp. The initiation site for translation was localized at nucleotide positions 158-160 and fulfilled the requirement for an adequate initiation site (Kozak, Critical Rev. Biochem. Mol. Biol. 27:385-402, 1992).

[0117]FIG. 12 shows the LPAAT amino acid sequence alignment from the human isoforms γ1, γ2, and δ. Amino acids identical in at least two sequences are highlighted. LPAAT-γ1 and LPAAT-δ have an overall amino acid match of 54% with respect to each other.

EXAMPLE 1

[0118] This example illustrates an experiment to determine if the human LPAATα clone encodes a protein with LPAAT activity, an E. coli vector expressing the human LPAATα as a fusion protein with β-galactosidase was transformed into a LPAAT minus strain of E. coli to see if it would complement the defect in E. coli. Specifically, the 840 bp Bgl II-Nco I fragment, which spans the coding region of human LPAATα from amino acid 68 to beyond the stop codon, derived from pZplat.11 was inserted into a Bgl II/Nco I digested cloning vector pLitmus28 (Evans et al., BioTechniques 19:130-135, 1995) to generate the plasmid p28BgN. This plasmid is expected to express the human LPAATα as a fusion protein containing the first 16 amino acids of β-galactosidase and the last 216 residues of the human LPAATα coding sequence using the lac promoter in pLitmus28. This plasmid was transformed into the E. coli strain JC201 (obtained from Dr. Jack Coleman, Louisiana State University). JC201 (Coleman, Mol. Gen. Genet. 232:295-303, 1992; Nagiec et al., J. Biol. Chem. 268:22156-22163, 1993; and Brown et al., Plant Mol. Biol. 26:211-223, 1994) is deficient in LPAAT activity due to mutation in the plsC locus. This mutation leads to a temperature-sensitive phenotype that causes JC201 to grow slowly at 37° C., almost not at all at 42° C., and not at all at 44° C. JC201 transformed with p28BgN was able to grow normally at 44° C. when compared to the wild type strain JC200 (plsC⁺), while JC201 transformed with pLitmus28 vector was not able to support growth at 44° C. These data suggest that the putative human LPAATα cDNA isolated here does possess LPAAT activity, as the last 216 amino acids of this cDNA is sufficient to complement the defective LPAAT gene (plsC) in JC201.

EXAMPLE 2

[0119] To see if the putative human LPAATβ clone encodes a protein with LPAAT activity, an E. coli vector expressing this human LPAATβ as a direct product was transformed into a LPAAT minus strain of E. coli to see if it would complement the defect in E. coli. Specifically, the 1350 bp Nco I-Xba I fragment from pSP.LPAT3, which spans the entire coding region from amino acid 1 to beyond the stop codon, was inserted into a Nco I/Xba I digested cloning vector pKK388-1 (Clontech, Palo Alto, Calif.) to generate the plasmid pTrc.LPAT3. This plasmid was transformed into the E. coli strain JC201 (obtained from Dr. Jack Coleman, Louisiana State University). JC201 (Coleman, Mol. Gen. Genet. 232:295-303, 1992) is deficient in LPAAT activity due to mutation in the plsC locus. This mutation leads to a temperature-sensitive phenotype that causes JC201 to grow slowly at 37° C., almost not at all at 42° C., and not at all at 44° C. JC201 transformed with pTrc.LPAT3 was able to grow normally at 44° C. when compared to the wild type strain JC200 (plsC⁺), while JC201 transformed with pKK388-1 vector was not able to support growth at 44° C. These data suggest that the putative human LPAATβ cDNA isolated here does possess LPAAT activity, as the putative protein product of this cDNA is able to complement the defective LPAAT gene (plsC) in JC201.

EXAMPLE 3

[0120] This example illustrates a group of experiments to see if overexpression of this human LPAATα would have any effect on mammalian cells. The entire cDNA insert (˜2,300 bp) from pZplat.11 was cleaved with Asp718 I and Xho I for insertion into the mammalian expression vector pCE9 to generate pCE9.LPAAT1. pCE9 was derived from pCE2 with two modifications. The 550 bp BstY I fragment within the elongation factor-1a (EF-1a) intron of pCE2 was deleted. The multiple cloning region of pCE2 between the Asp718 I and BamH I site was replaced with the multiple cloning region spanning the Asp718 I and Bgl II sites from pLitmus28. The plasmid pCE2 was derived from pREP7b (Leung, et al., Proc. Natl. Acad. Sci. USA, 92: 4813-4817, 1995) with the RSV promoter region replaced by the CMV enhancer and the elongation factor-1a (EF-1a) promoter and intron. The CMV enhancer came from a 380 bp Xba I-Sph I fragment produced by PCR from pCEP4 (Invitrogen, San Diego, Calif.) using the primers 5′-GGCTCTAGAT ATTAATAGTA ATCAATTAC-3′ and 5′-CCTCACGCAT GCACCATGGT AATAGC-3′. The EF-1a promoter and intron (Uetsuki, et al., J. Biol. Chem., 264: 5791-5798, 1989) came from a 1200 bp Sph I-Asp718 I fragment produced by PCR from human genomic DNA using the primers 5′-GGTGCATGCG TGAGGCTCCG GTGC-3′ and 5′-GTAGTTTTCA CGGTACCTGA AATGGAAG-3′. These 2 fragments were ligated into a Xba I/Asp718 I digested vector derived from pREP7b to generate pCE2.

[0121] pCE9.LPAAT1 DNA was transfected into several mammalian cell lines, including A549 cells, ECV304 cells (American Type Culture Collection, Rockville, Md.), two human cell line that would produce IL-6 and TNF upon stimulation with IL-1b and murine TNF and 293-EBNA cells (Invitrogen, San Diego, Calif.). pCE9.LPAAT1 was digested with BspH I before electroporating into these cell lines with a Cell-Porator™ (Life Technologies, Gaithersburg, Md.) using conditions described previously (Cachianes, et al., Biotechniques 15:255-259, 1993). After adherence of the transfected cells 24 hours later, the cells were grown in the presence of 200 μg/ml Hygromycin B (Hyg) (Calbiochem, La Jolla, Calif.) to select for cells that had incorporated both plasmids. Hyg-resistant clones that expressed LPAAT mRNA at a level more than 20 fold higher relative to untransfected cells based on Northern Blot analysis (Kroczek, et al., Anal. Biochem. 184: 90-95, 1990) were selected for further study.

[0122]FIG. 6 compares the LPAAT activity in A549 cells and in A549 cells transfected with pCE9.LPAAT1 DNA using a TLC assay. This screening assay for LPAAT activity in cell extracts was based on a fluorecent assay using fluorescent lipid substrates (Ella, et al., Anal Biochem. 218: 136-142, 1994). Instead of using the PC-substrate, BPC (Molecular Probes, Eugene, Oreg.), a synthetic PC that contains an ether linkage at the SN1 position with a fluorescent Bodipy moiety incorporated into the end of the alkyl-chain at the SN1 position, BPC was converted to Bodipy-PA using cabbage phospholipase D (Sigma, St. Louis, Mo.). Bodipy-PA was then converted to Bodipy-LPA using snake venom phospholipase A2. The Bodipy-LPA obtained was purified by preparative TLC for use in the LPAAT assay. The assay was carried out in total cell extracts resuspended in lysis buffer (Ella, et al., Anal. Biochem. 218: 136-142, 1994) supplemented with 0.5 mM ATP, 0.3 mM MgCl₂, 100 μM oleoyl-CoA and 10 μM Bodipy LPA. The samples were incubated for 30 min before loading onto TLC plates.

[0123] Lane 1 refers to Bodipy LPA incubated with buffer only without any cell extract added. Lane 9 refers to BPC treated with cabbage phospholipase D for generating a Bodipy-PA marker. Lanes 2 and 4 refer to Bodipy LPA incubated with control A549 cell extracts with or without lipid A, respectively. Lanes 3 and 5 refer to Bodipy LPA incubated with A549 cell extracts transfected with pCE9.LPAAT1 DNA with or without lipid A, respectively. FIG. 3 shows A549 cells transfected with the LPAAT cDNA (lanes 3 and 5) contain much more LPAAT activity than those of control cells (lanes 2 and 4) as evidenced by the increased conversion of Bodipy-LPA to Bodipy-PA. Addition of lipid A to the cell extracts has little effect on LPAAT activity (lanes 2 vs 4 and 3 vs 5). A549 cell extract also contains a phosphohydrolase activity that converts Bodipy-LPA to Bodipy-monoalkylglycerol (lanes 2 to 5). Interestingly, A549 cells overexpressing LPAAT (lanes 3 and 5) have less of this activity compared to control cells (lanes 2 and 4), suggesting this phosphohydrolase prefers LPA to PA as substrate. There is also an increase of DAG in transfected cells (lanes 3 and 5) compared to control cells (lanes 2 and 4) possibly due to partial conversion of the PA formed to DAG from this endogenous phosphohydrolase.

EXAMPLE 4

[0124] To see if the expressed LPAAT cDNA clone described here would also use other glycerol-lipids that contain a free-hydroxyl group at the SN2 position, the cell extracts were incubated with the substrates NBD-lysoPC (lanes 6 and 7) and NBD-monoacylglycerol (MAG) (lanes 10 and 11) to see if there is increased conversion to lysoPC and DAG, respectively. Lane 8 and 12 refer, respectively, to NBD-lysoPC and NBD-MAG incubated with buffer only without any cell extract added. TLC analysis shows little difference in the lipid profile between the transfected and control cells (lanes 7 vs 6, lanes 11 vs 10), suggesting the cloned LPAAT enzyme uses LPA as the preferred substrate. It is likely that the acyltransferases for lysoPC (Fyrst, et al., Biochem. J. 306:793-799, 1995) and for MAG (Bhat, et al., Biochemistry 34: 11237-11244, 1995) represent different enzymes from the LPAAT described here.

EXAMPLE 5

[0125] pCE9.LPAAT1 DNA was transfected into A549 cells (American Type Culture Collection, Rockville, Md.), a human cell line that would produce IL-6 and TNF upon stimulation with IL-1β and murine TNF. pCE9.LPAAT1 was digested with BspH I before electroporating into A549 cells with a Cell-Porator™ (Life Technologies, Gaithersburg, Md.) using conditions described previously (Cachianes, et al., Biotechniques 15:255-259, 1993). After adherence of the transfected cells 24 hours later, the cells were grown in the presence of 200 μg/ml Hygromycin B (Hyg) (Calbiochem, La Jolla, Calif.) to select for cells that had incorporated both plasmids. A Hyg-resistant clone that expressed LPAAT mRNA at a level more than 20 fold higher relative to untransfected A549 cells based on Northern Blot analysis (Kroczek et al., Anal. Biochem. 184:90-95, 1990) was selected for further study.

[0126] A comparison of the production of TNF (FIG. 7) and IL-6 (FIG. 8) between A549 cells transfected with pCE9.LPAAT1 and control A549 cells after stimulation with IL-1β and murine TNF shows A549 overexpressing LPAAT produces >5 fold more TNF and >10 fold more IL-6 relative to untransfected A549 cells, suggesting that overexpression of LPAAT would enhance the cytokine signaling response in cells. Development of compounds that would modulate LPAAT activity should therefore be of therapeutic interest in the field of inflammation.

EXAMPLE 6

[0127] Construction of pC9LPTγ1 and pC2LPTδ: The primers 5′-ggcccggtacc ATGGGCCTG CTGGCCTTC C-3′ (oLPγ1_(—)1F) and 5′-taactcCTCGAG TTATTCCTT TTTCTTAAA CTC-3′ (oLPγ1_(—)1R) were used to amplify the 1100 bp Acc65 I-XhoI fragment by PCR from the template pSK_LPg1. The fragment generated was then inserted into a Acc65 I/Xho I digested pCE9 (West, et al., DNA Cell Biol. 6: 691-701, 1997) expression vector to make pC9LPTγ1. Similarly, the primers 5′-atggtggtaccacc ATGGACCTC GCGGGACTG CTG-3′ (oLPTγ_(—)1F) and 5′-GGAgGATATc tAGAgGCCAC CAGTTC-3′ (oLPTδ_(—)1R) were used to amplify the 1100 bp Acc65 I-Xba I fragment by PCR from the template #H18562. The fragment generated was then inserted into a Acc65 I/Nhe I digested pCE2 (West, et al., DNA Cell Biol. 6: 691-701, 1997) expression vector to make pC2LPTδ.

EXAMPLE 7

[0128] Expression of hLPAATγ1 and hLPAATδ in mammalian cells. Plasmids pC9LPTγ1 or pC2LPTδ were stably transfected into endothelial ECV304 cells (American Type Culture Collection, Rockville, Md.). Specifically, pC9LPTγ1 or pC2LPTδ were digested with BspH I before electroporating into these cell lines with a Cell-Porator™ (Life Technologies, Gaithersburg, Md.). After adherence of the transfected cells 24 hours later, the cells were grown in the presence of 500 μg/ml Hygromycin B (Hyg) (Calbiochem, La Jolla, Calif.) to select for cells that had incorporated plasmids. Hyg-resistant clones that expressed LPAAT-γ1 or LPAAT-δ mRNA at a level more than 10 fold higher than that of cells transfected with pCE9 or pCE2 vector, based on Northern Blot analysis, were selected for further study.

[0129]FIG. 13 compares the LPAAT activity in ECV304 cells stably transfected with the expression plasmids for LPAAT-α (pCE9.LPAAT-α), LPAAT-β (pCE9.LPAAT-β) DNA, LPAAT-γ1 (pC9LPTγ1), LPAAT-δ (pC2LPTδ), or the control vector (pCE9). This screening assay for LPAAT activity in cell extracts was based on the conversion of [¹⁴C]oleoyl-CoA to [¹⁴C]PA using a TLC assay. The assay was carried out in total cell extracts resuspended in lysis buffer (Ella, et al., Anal. Biochem. 218: 136-142, 1994) supplemented with 50 μM [¹⁴C]oleoyl-CoA and 200 μM LPA. The samples were incubated for 10 min, extracted from chloroform, before loading onto TLC plates. Lanes 1 and 2 refer to [¹⁴C]oleoyl-CoA and LPA incubated with cell extract transfected with LPAAT-α plasmid; lanes 3 and 4, with LPAAT-β plasmid; lanes 5 and 6, with LPAAT-γ1 plasmid; lanes 7 and 8, with LPAAT-δ plasmid; and lanes 9 and 10, with control vector. ECV304 cells transfected with LPAAT-α or -β cDNA (lanes 1 to 4) contain more than 3 and 20 times, respectively, LPAAT activity when compared to those of control cells (lanes 9 and 10) as evidenced by the increased conversion of [¹⁴C]oleoyl-CoA to [¹⁴C]PA. Cells transfected with LPAAT-δ cDNA (lanes 7 and 8) contain about 2.5 times more LPAAT activity than those of control cells (lanes 9 and 10), whereas cells transfected with LPAAT-δ cDNA show no increase in activity when compared to those of control cells (lanes 9 and 10).

1 42 1 2242 DNA Homo sapiens CDS (319)..(1167) 1 ggaagtcagc aggcgttggg gaggggtggc gggggaatag cggcggcagc agccccagcc 60 ctcagagaga cagcagaaag ggagggaggg agggtgctgg ggggacagcc ccccaccatt 120 cctaccgcta tgggcccaac ctcccactcc cacctcccct ccatcggccg gggctaggac 180 acccccaaat cccgtcgccc ccttggcacc gacaccccga cagagacaga gacacagcca 240 tccgccacca ccgctgccgc agcctggctg gggagggggc cagcccccca ggccccctac 300 ccctctgagg tggccaga atg gat ttg tgg cca ggg gca tgg atg ctg ctg 351 Met Asp Leu Trp Pro Gly Ala Trp Met Leu Leu 1 5 10 ctg ctg ctc ttc ctg ctg ctg ctc ttc ctg ctg ccc acc ctg tgg ttc 399 Leu Leu Leu Phe Leu Leu Leu Leu Phe Leu Leu Pro Thr Leu Trp Phe 15 20 25 tgc agc ccc agt gcc aag tac ttc ttc aag atg gcc ttc tac aat ggc 447 Cys Ser Pro Ser Ala Lys Tyr Phe Phe Lys Met Ala Phe Tyr Asn Gly 30 35 40 tgg atc ctc ttc ctg gct gtg ctc gcc atc cct gtg tgt gcc gtg cga 495 Trp Ile Leu Phe Leu Ala Val Leu Ala Ile Pro Val Cys Ala Val Arg 45 50 55 gga cgc aac gtc gag aac atg aag atc ttg cgt cta atg ctg ctc cac 543 Gly Arg Asn Val Glu Asn Met Lys Ile Leu Arg Leu Met Leu Leu His 60 65 70 75 atc aaa tac ctg tac ggg atc cga gtg gag gtg cga ggg gct cac cac 591 Ile Lys Tyr Leu Tyr Gly Ile Arg Val Glu Val Arg Gly Ala His His 80 85 90 ttc cct ccc tcg cag ccc tat gtt gtt gtc tcc aac cac cag agc tct 639 Phe Pro Pro Ser Gln Pro Tyr Val Val Val Ser Asn His Gln Ser Ser 95 100 105 ctc gat ctg ctt ggg atg atg gag gta ctg cca ggc cgc tgt gtg ccc 687 Leu Asp Leu Leu Gly Met Met Glu Val Leu Pro Gly Arg Cys Val Pro 110 115 120 att gcc aag cgc gag cta ctg tgg gct ggc tct gcc ggg ctg gcc tgc 735 Ile Ala Lys Arg Glu Leu Leu Trp Ala Gly Ser Ala Gly Leu Ala Cys 125 130 135 tgg ctg gca gga gtc atc ttc atc gac cgg aag cgc acg ggg gat gcc 783 Trp Leu Ala Gly Val Ile Phe Ile Asp Arg Lys Arg Thr Gly Asp Ala 140 145 150 155 atc agt gtc atg tct gag gtc gcc cag acc ctg ctc acc cag gac gtg 831 Ile Ser Val Met Ser Glu Val Ala Gln Thr Leu Leu Thr Gln Asp Val 160 165 170 agg gtc tgg gtg ttt cct gag gga acg aga aac cac aat ggc tcc atg 879 Arg Val Trp Val Phe Pro Glu Gly Thr Arg Asn His Asn Gly Ser Met 175 180 185 ctg ccc ttc aaa cgt ggc gcc ttc cat ctt gca gtg cag gcc cag gtt 927 Leu Pro Phe Lys Arg Gly Ala Phe His Leu Ala Val Gln Ala Gln Val 190 195 200 ccc att gtc ccc ata gtc atg tcc tcc tac caa gac ttc tac tgc aag 975 Pro Ile Val Pro Ile Val Met Ser Ser Tyr Gln Asp Phe Tyr Cys Lys 205 210 215 aag gag cgt cgc ttc acc tcg gga caa tgt cag gtg cgg gtg ctg ccc 1023 Lys Glu Arg Arg Phe Thr Ser Gly Gln Cys Gln Val Arg Val Leu Pro 220 225 230 235 cca gtg ccc acg gaa ggg ctg aca cca gat gac gtc cca gct ctg gct 1071 Pro Val Pro Thr Glu Gly Leu Thr Pro Asp Asp Val Pro Ala Leu Ala 240 245 250 gac aga gtc cgg cac tcc atg ctc act gtt ttc cgg gaa atc tcc act 1119 Asp Arg Val Arg His Ser Met Leu Thr Val Phe Arg Glu Ile Ser Thr 255 260 265 gat ggc cgg ggt ggt ggt gac tat ctg aag aag cct ggg ggc ggt ggg 1167 Asp Gly Arg Gly Gly Gly Asp Tyr Leu Lys Lys Pro Gly Gly Gly Gly 270 275 280 tgaaccctgg ctctgagctc tcctcccatc tgtccccatc ttcctcccca cacctaccca 1227 cccagtgggc cctgaagcag ggccaaaccc tcttccttgt ctcccctctc cccacttatt 1287 ctcctctttg gaatcttcaa cttctgaagt gaatgtggat acagcgccac tcctgccccc 1347 tcttggcccc atccatggac tcttgcctcg gtgcagtttc cactcttgac ccccacctcc 1407 tactgtcttg tctgtgggac agttgcctcc ccctcatctc cagtgactca gcctacacaa 1467 gggaggggaa cattccatcc ccagtggagt ctcttcctat gtggtcttct ctacccctct 1527 acccccacat tggccagtgg actcatccat tctttggaac aaatcccccc ccactccaaa 1587 gtccatggat tcaatggact catccatttg tgaggaggac ttctcgccct ctggctggaa 1647 gctgatacct gaagcactcc caggctcatc ctgggagctt tcctcagcac cttcaccttc 1707 cctcccagtg tagcctcctg tcagtggggg ctggaccctt ctaattcaga ggtctcatgc 1767 ctgcccttgc ccagatgccc agggtcgtgc actctctggg ataccagttc agtctccaca 1827 tttctggttt tctgtcccca tagtacagtt cttcagtgga catgacccca cccagccccc 1887 tgcagccctg ctgaccatct caccagacac aaggggaaga agcagacatc aggtgctgca 1947 ctcacttctg ccccctgggg agttggggaa aggaacgaac cctggctgga ggggatagga 2007 gggcttttaa tttatttctt tttctgttga ggcttccccc tctctgagcc agttttcatt 2067 tcttcctggt ggcattagcc actccctgcc tctcactcca gacctgttcc cacaactggg 2127 gaggtaggct gggagcaaaa ggagagggtg ggacccagtt ttgcgtggtt ggtttttatt 2187 aattatctgg ataacagcaa aaaaactgaa aataaagaga gagagaaaaa aaaaa 2242 2 283 PRT Homo sapiens 2 Met Asp Leu Trp Pro Gly Ala Trp Met Leu Leu Leu Leu Leu Phe Leu 1 5 10 15 Leu Leu Leu Phe Leu Leu Pro Thr Leu Trp Phe Cys Ser Pro Ser Ala 20 25 30 Lys Tyr Phe Phe Lys Met Ala Phe Tyr Asn Gly Trp Ile Leu Phe Leu 35 40 45 Ala Val Leu Ala Ile Pro Val Cys Ala Val Arg Gly Arg Asn Val Glu 50 55 60 Asn Met Lys Ile Leu Arg Leu Met Leu Leu His Ile Lys Tyr Leu Tyr 65 70 75 80 Gly Ile Arg Val Glu Val Arg Gly Ala His His Phe Pro Pro Ser Gln 85 90 95 Pro Tyr Val Val Val Ser Asn His Gln Ser Ser Leu Asp Leu Leu Gly 100 105 110 Met Met Glu Val Leu Pro Gly Arg Cys Val Pro Ile Ala Lys Arg Glu 115 120 125 Leu Leu Trp Ala Gly Ser Ala Gly Leu Ala Cys Trp Leu Ala Gly Val 130 135 140 Ile Phe Ile Asp Arg Lys Arg Thr Gly Asp Ala Ile Ser Val Met Ser 145 150 155 160 Glu Val Ala Gln Thr Leu Leu Thr Gln Asp Val Arg Val Trp Val Phe 165 170 175 Pro Glu Gly Thr Arg Asn His Asn Gly Ser Met Leu Pro Phe Lys Arg 180 185 190 Gly Ala Phe His Leu Ala Val Gln Ala Gln Val Pro Ile Val Pro Ile 195 200 205 Val Met Ser Ser Tyr Gln Asp Phe Tyr Cys Lys Lys Glu Arg Arg Phe 210 215 220 Thr Ser Gly Gln Cys Gln Val Arg Val Leu Pro Pro Val Pro Thr Glu 225 230 235 240 Gly Leu Thr Pro Asp Asp Val Pro Ala Leu Ala Asp Arg Val Arg His 245 250 255 Ser Met Leu Thr Val Phe Arg Glu Ile Ser Thr Asp Gly Arg Gly Gly 260 265 270 Gly Asp Tyr Leu Lys Lys Pro Gly Gly Gly Gly 275 280 3 303 PRT Yeast 3 Met Ser Val Ile Gly Arg Phe Leu Tyr Tyr Leu Arg Ser Val Leu Val 1 5 10 15 Val Leu Ala Leu Ala Gly Cys Gly Phe Tyr Gly Val Ile Ala Ser Ile 20 25 30 Leu Cys Thr Leu Ile Gly Lys Gln His Leu Ala Gln Trp Ile Thr Ala 35 40 45 Arg Cys Phe Tyr His Val Met Lys Leu Met Leu Gly Leu Asp Val Lys 50 55 60 Val Val Gly Glu Glu Asn Leu Ala Lys Lys Pro Tyr Ile Met Ile Ala 65 70 75 80 Asn His Gln Ser Thr Leu Asp Ile Phe Met Leu Gly Arg Ile Phe Pro 85 90 95 Pro Gly Cys Thr Val Thr Ala Lys Lys Ser Leu Lys Tyr Val Pro Phe 100 105 110 Leu Gly Trp Phe Met Ala Leu Ser Gly Thr Tyr Phe Leu Asp Arg Ser 115 120 125 Lys Arg Gln Glu Ala Ile Asp Thr Leu Asn Lys Gly Leu Glu Asn Val 130 135 140 Lys Lys Asn Lys Arg Ala Leu Trp Val Phe Pro Glu Gly Thr Arg Ser 145 150 155 160 Tyr Thr Ser Glu Leu Thr Met Leu Pro Phe Lys Lys Gly Ala Phe His 165 170 175 Leu Ala Gln Gln Gly Lys Ile Pro Ile Val Pro Val Val Val Ser Asn 180 185 190 Thr Ser Thr Leu Val Ser Pro Lys Tyr Gly Val Phe Asn Arg Gly Cys 195 200 205 Met Ile Val Arg Ile Leu Lys Pro Ile Ser Thr Glu Asn Leu Thr Lys 210 215 220 Asp Lys Ile Gly Glu Phe Ala Glu Lys Val Arg Asp Gln Met Val Asp 225 230 235 240 Thr Leu Lys Glu Ile Gly Tyr Ser Pro Ala Ile Asn Asp Thr Thr Leu 245 250 255 Pro Pro Gln Ala Ile Glu Tyr Ala Ala Leu Gln His Asp Lys Lys Val 260 265 270 Asn Lys Lys Ile Lys Asn Glu Pro Val Pro Ser Val Ser Ile Ser Asn 275 280 285 Asp Val Asn Thr His Asn Glu Gly Ser Ser Val Lys Lys Met His 290 295 300 4 245 PRT E. coli 4 Met Leu Tyr Ile Phe Arg Leu Ile Ile Thr Val Ile Tyr Ser Ile Leu 1 5 10 15 Val Cys Val Phe Gly Ser Ile Tyr Cys Leu Phe Ser Pro Arg Asn Pro 20 25 30 Lys His Val Ala Thr Phe Gly His Met Phe Gly Arg Leu Ala Pro Leu 35 40 45 Phe Gly Leu Lys Val Glu Cys Arg Lys Pro Thr Asp Ala Glu Ser Tyr 50 55 60 Gly Asn Ala Ile Tyr Ile Ala Asn His Gln Asn Asn Tyr Asp Met Val 65 70 75 80 Thr Ala Ser Asn Ile Val Gln Pro Pro Thr Val Thr Val Gly Lys Lys 85 90 95 Ser Leu Leu Trp Ile Pro Phe Phe Gly Gln Leu Tyr Trp Leu Thr Gly 100 105 110 Asn Leu Leu Ile Asp Arg Asn Asn Arg Thr Lys Ala His Gly Thr Ile 115 120 125 Ala Glu Val Val Asn His Phe Lys Lys Arg Arg Ile Ser Ile Trp Met 130 135 140 Phe Pro Glu Gly Thr Arg Ser Arg Gly Arg Gly Leu Leu Pro Phe Lys 145 150 155 160 Thr Gly Ala Phe His Ala Ala Ile Ala Ala Gly Val Pro Ile Ile Pro 165 170 175 Val Cys Val Ser Thr Thr Ser Asn Lys Ile Asn Leu Asn Arg Leu His 180 185 190 Asn Gly Leu Val Ile Val Glu Met Leu Pro Pro Ile Asp Val Ser Gln 195 200 205 Tyr Gly Lys Asp Gln Val Arg Glu Leu Ala Ala His Cys Arg Ser Ile 210 215 220 Met Glu Gln Lys Ile Ala Glu Leu Asp Lys Glu Val Ala Glu Arg Glu 225 230 235 240 Ala Ala Gly Lys Val 245 5 374 PRT Maize 5 Met Ala Ile Pro Leu Val Leu Val Val Leu Pro Leu Gly Leu Leu Phe 1 5 10 15 Leu Leu Ser Gly Leu Ile Val Asn Ala Ile Gln Ala Val Leu Phe Val 20 25 30 Thr Ile Arg Pro Phe Ser Lys Ser Phe Tyr Arg Arg Ile Asn Arg Phe 35 40 45 Leu Ala Glu Leu Leu Trp Leu Gln Leu Val Trp Val Val Asp Trp Trp 50 55 60 Ala Gly Val Lys Val Gln Leu His Ala Asp Glu Glu Thr Tyr Arg Ser 65 70 75 80 Met Gly Lys Glu His Ala Leu Ile Ile Ser Asn His Arg Ser Asp Ile 85 90 95 Asp Trp Leu Ile Gly Trp Ile Leu Ala Gln Arg Ser Gly Cys Leu Gly 100 105 110 Ser Thr Leu Ala Val Met Lys Lys Ser Ser Lys Phe Leu Pro Val Ile 115 120 125 Gly Trp Ser Met Trp Phe Ala Glu Tyr Leu Phe Leu Glu Arg Ser Trp 130 135 140 Ala Lys Asp Glu Lys Thr Leu Lys Trp Gly Leu Gln Arg Leu Lys Asp 145 150 155 160 Phe Pro Arg Pro Phe Trp Leu Ala Leu Phe Val Glu Gly Thr Arg Phe 165 170 175 Thr Pro Ala Lys Leu Leu Ala Ala Gln Glu Tyr Ala Ala Ser Gln Gly 180 185 190 Leu Pro Ala Pro Arg Asn Val Leu Ile Pro Arg Thr Lys Gly Phe Val 195 200 205 Ser Ala Val Ser Ile Met Arg Asp Phe Val Pro Ala Ile Tyr Asp Thr 210 215 220 Thr Val Ile Val Pro Lys Asp Ser Pro Gln Pro Thr Met Leu Arg Ile 225 230 235 240 Leu Lys Gly Gln Ser Ser Val Ile His Val Arg Met Lys Arg His Ala 245 250 255 Met Ser Glu Met Pro Lys Ser Asp Glu Asp Val Ser Lys Trp Cys Lys 260 265 270 Asp Ile Phe Val Ala Lys Asp Ala Leu Leu Asp Lys His Leu Ala Thr 275 280 285 Gly Thr Phe Asp Glu Glu Ile Arg Pro Ile Gly Arg Pro Val Lys Ser 290 295 300 Leu Leu Val Thr Leu Phe Trp Ser Cys Leu Leu Leu Phe Gly Ala Ile 305 310 315 320 Glu Phe Phe Lys Trp Thr Gln Leu Leu Ser Thr Trp Arg Gly Val Ala 325 330 335 Phe Thr Ala Ala Gly Met Ala Leu Val Thr Gly Val Met His Val Phe 340 345 350 Ile Met Phe Ser Gln Ala Glu Arg Ser Ser Ser Ala Arg Ala Ala Arg 355 360 365 Asn Arg Val Lys Lys Glu 370 6 1383 DNA Homo sapiens CDS (40)..(876) 6 ggagcgagct ggcggcgccg tcgggcgccg ggccgggcc atg gag ctg tgg ccg 54 Met Glu Leu Trp Pro 1 5 tgt ctg gcc gcg gcg ctg ctg ttg ctg ctg ctg ctg gtg cag ctg agc 102 Cys Leu Ala Ala Ala Leu Leu Leu Leu Leu Leu Leu Val Gln Leu Ser 10 15 20 cgc gcg gcc gag ttc tac gcc aag gtc gcc ctg tac tgc gcg ctg tgc 150 Arg Ala Ala Glu Phe Tyr Ala Lys Val Ala Leu Tyr Cys Ala Leu Cys 25 30 35 ttc acg gtg tcc gcc gtg gcc tcg ctc gtc tgc ctg ctg tgc cac ggc 198 Phe Thr Val Ser Ala Val Ala Ser Leu Val Cys Leu Leu Cys His Gly 40 45 50 ggc cgg acg gtg gag aac atg agc atc atc ggc tgg ttc gtg cga agc 246 Gly Arg Thr Val Glu Asn Met Ser Ile Ile Gly Trp Phe Val Arg Ser 55 60 65 ttc aag tac ttt tac ggg ctc cgc ttc gag gtg cgg gac ccg cgc agg 294 Phe Lys Tyr Phe Tyr Gly Leu Arg Phe Glu Val Arg Asp Pro Arg Arg 70 75 80 85 ctg cag gag gcc cgt ccc tgt gtc atc gtc tcc aac cac cag agc atc 342 Leu Gln Glu Ala Arg Pro Cys Val Ile Val Ser Asn His Gln Ser Ile 90 95 100 ctg gac atg atg ggc ctc atg gag gtc ctt ccg gag cgc tgc gtg cag 390 Leu Asp Met Met Gly Leu Met Glu Val Leu Pro Glu Arg Cys Val Gln 105 110 115 atc gcc aag cgg gag ctg ctc ttc ctg ggg ccc gtg ggc ctc atc atg 438 Ile Ala Lys Arg Glu Leu Leu Phe Leu Gly Pro Val Gly Leu Ile Met 120 125 130 tac ctc ggg ggc gtc ttc ttc atc aac cgg cag cgc tct agc act gcc 486 Tyr Leu Gly Gly Val Phe Phe Ile Asn Arg Gln Arg Ser Ser Thr Ala 135 140 145 atg aca gtg atg gcc gac ctg ggc gag cgc atg gtc agg gag aac ctc 534 Met Thr Val Met Ala Asp Leu Gly Glu Arg Met Val Arg Glu Asn Leu 150 155 160 165 aaa gtg tgg atc tat ccc gag ggt act cgc aac gac aat ggg gac ctg 582 Lys Val Trp Ile Tyr Pro Glu Gly Thr Arg Asn Asp Asn Gly Asp Leu 170 175 180 ctg cct ttt aag aag ggc gcc ttc tac ctg gca gtc cag gca cag gtg 630 Leu Pro Phe Lys Lys Gly Ala Phe Tyr Leu Ala Val Gln Ala Gln Val 185 190 195 ccc atc gtc ccc gtg gtg tac tct tcc ttc tcc tcc ttc tac aac acc 678 Pro Ile Val Pro Val Val Tyr Ser Ser Phe Ser Ser Phe Tyr Asn Thr 200 205 210 aag aag aag ttc ttc act tca gga aca gtc aca gtg cag gtg ctg gaa 726 Lys Lys Lys Phe Phe Thr Ser Gly Thr Val Thr Val Gln Val Leu Glu 215 220 225 gcc atc ccc acc agc ggc ctc act gcg gcg gac gtc cct gcg ctc gtg 774 Ala Ile Pro Thr Ser Gly Leu Thr Ala Ala Asp Val Pro Ala Leu Val 230 235 240 245 gac acc tgc cac cgg gcc atg agg acc acc ttc ctc cac atc tcc aag 822 Asp Thr Cys His Arg Ala Met Arg Thr Thr Phe Leu His Ile Ser Lys 250 255 260 acc ccc cag gag aac ggg gcc act gcg ggg tct ggc gtg cag ccg gcc 870 Thr Pro Gln Glu Asn Gly Ala Thr Ala Gly Ser Gly Val Gln Pro Ala 265 270 275 cag tag cccagaccac ggcagggcat gacctgggga gggcaggtgg aagccgatgg 926 Gln ctggaggatg ggcagagggg actcctcccg gcttccaaat accactctgt ccggctcccc 986 cagctctcac tcagcccggg aagcaggaag ccccttctgt cactggtctc agacacaggc 1046 ccctggtgtc ccctgcaggg ggctcagctg gaccctcccc gggctcgagg gcagggactc 1106 gcgcccacgg cacctctggg ngctgggntg ataaagatga ggcttgcggc tgtggcccgc 1166 tggtgggctg agccacaagg cccccgatgg cccaggagca gatgggagga ccccgaggcc 1226 aggagtccca gactcacgca ccctgggcca cagggagccg ggaatcgggg cctgctgctc 1286 ctgctggcct gaagaatctg tggggtcagc actgtactcc gttgctgttt ttttataaac 1346 acactcttgg aaaaaaaaaa aaaaaaaaaa aaaaaaa 1383 7 278 PRT Homo sapiens 7 Met Glu Leu Trp Pro Cys Leu Ala Ala Ala Leu Leu Leu Leu Leu Leu 1 5 10 15 Leu Val Gln Leu Ser Arg Ala Ala Glu Phe Tyr Ala Lys Val Ala Leu 20 25 30 Tyr Cys Ala Leu Cys Phe Thr Val Ser Ala Val Ala Ser Leu Val Cys 35 40 45 Leu Leu Cys His Gly Gly Arg Thr Val Glu Asn Met Ser Ile Ile Gly 50 55 60 Trp Phe Val Arg Ser Phe Lys Tyr Phe Tyr Gly Leu Arg Phe Glu Val 65 70 75 80 Arg Asp Pro Arg Arg Leu Gln Glu Ala Arg Pro Cys Val Ile Val Ser 85 90 95 Asn His Gln Ser Ile Leu Asp Met Met Gly Leu Met Glu Val Leu Pro 100 105 110 Glu Arg Cys Val Gln Ile Ala Lys Arg Glu Leu Leu Phe Leu Gly Pro 115 120 125 Val Gly Leu Ile Met Tyr Leu Gly Gly Val Phe Phe Ile Asn Arg Gln 130 135 140 Arg Ser Ser Thr Ala Met Thr Val Met Ala Asp Leu Gly Glu Arg Met 145 150 155 160 Val Arg Glu Asn Leu Lys Val Trp Ile Tyr Pro Glu Gly Thr Arg Asn 165 170 175 Asp Asn Gly Asp Leu Leu Pro Phe Lys Lys Gly Ala Phe Tyr Leu Ala 180 185 190 Val Gln Ala Gln Val Pro Ile Val Pro Val Val Tyr Ser Ser Phe Ser 195 200 205 Ser Phe Tyr Asn Thr Lys Lys Lys Phe Phe Thr Ser Gly Thr Val Thr 210 215 220 Val Gln Val Leu Glu Ala Ile Pro Thr Ser Gly Leu Thr Ala Ala Asp 225 230 235 240 Val Pro Ala Leu Val Asp Thr Cys His Arg Ala Met Arg Thr Thr Phe 245 250 255 Leu His Ile Ser Lys Thr Pro Gln Glu Asn Gly Ala Thr Ala Gly Ser 260 265 270 Gly Val Gln Pro Ala Gln 275 8 248 PRT H. influenzae 8 Met Leu Lys Leu Leu Arg Ile Phe Leu Val Leu Ile Cys Cys Ile Leu 1 5 10 15 Ile Cys Val Leu Gly Thr Ile Tyr Ser Phe Ile Arg Phe Lys Asn Pro 20 25 30 Ser Asn Val Gly Ile Val Ala Arg Trp Phe Gly Arg Leu Phe Thr Tyr 35 40 45 Pro Leu Phe Gly Leu Lys Val Glu His Arg Ile Pro Gln Asp Gln Lys 50 55 60 Gln Ile Ser Arg Ala Ile Tyr Ile Gly Asn His Gln Asn Asn Tyr Asp 65 70 75 80 Met Val Thr Ile Ser Tyr Met Val Gln Pro Arg Thr Val Ser Val Gly 85 90 95 Lys Lys Ser Leu Ile Trp Ile Pro Phe Phe Phe Thr Gly Ile Leu Tyr 100 105 110 Trp Val Thr Gly Asn Ile Phe Leu Asp Arg Glu Asn Arg Thr Lys Ala 115 120 125 His Asn Thr Met Ser Gln Leu Ala Arg Arg Ile Asn Glu Asp Asn Leu 130 135 140 Ser Ile Trp Met Phe Pro Glu Gly Thr Arg Asn Arg Gly Arg Gly Leu 145 150 155 160 Leu Pro Phe Lys Thr Gly Ala Phe Thr Phe His Ala Ala Ile Ser Ala 165 170 175 Gly Val Pro Ile Ile Pro Val Val Cys Ser Ser Thr His Asn Lys Ile 180 185 190 Asn Leu Asn Arg Trp Asp Asn Gly Lys Val Ile Cys Glu Ile Met Asp 195 200 205 Pro Ile Asp Val Ser Gly Tyr Thr Lys Asp Asn Val Arg Asp Leu Ala 210 215 220 Ala Tyr Cys His Phe Thr Asp Leu Met Glu Lys Arg Ile Ala Glu Leu 225 230 235 240 Asp Glu Glu Ile Ala Lys Gly Asn 245 9 253 PRT S. typhimuriu 9 Met Leu Tyr Ile Phe Arg Leu Ile Val Thr Val Ile Tyr Ser Ile Leu 1 5 10 15 Val Cys Val Phe Gly Ser Ile Tyr Cys Leu Phe Ser Pro Arg Asn Pro 20 25 30 Lys His Val Ala Thr Phe Gly His Met Phe Gly Arg Leu Phe Thr Ala 35 40 45 Pro Leu Phe Gly Leu Lys Val Glu Cys Arg Lys Pro Ala Asp Ala Glu 50 55 60 Asn Tyr Gly Asn Ala Ile Tyr Ile Ala Asn His Gln Asn Asn Tyr Asp 65 70 75 80 Met Val Thr Ala Ala Asn Ile Val Gln Pro Pro Thr Val Thr Val Gly 85 90 95 Lys Lys Ser Leu Leu Trp Ile Pro Phe Phe Phe Thr Gly Gln Leu Tyr 100 105 110 Trp Leu Thr Gly Asn Leu Leu Ile Asp Arg Asn Asn Arg Ala Lys Ala 115 120 125 His Ser Thr Ile Ala Ala Val Val Asn His Phe Lys Lys Arg Arg Ile 130 135 140 Ser Ile Trp Met Phe Pro Glu Gly Thr Arg Ser Arg Gly Arg Gly Leu 145 150 155 160 Leu Pro Phe Lys Thr Gly Ala Phe Thr Phe His Ala Ala Ile Ala Ala 165 170 175 Gly Val Pro Ile Ile Pro Val Cys Val Ser Asn Thr Ser Asn Lys Val 180 185 190 Asn Leu Asn Arg Leu Asn Asn Gly Leu Val Ile Val Glu Met Leu Pro 195 200 205 Pro Val Asp Val Ser Glu Tyr Gly Lys Asp Gln Val Arg Glu Leu Ala 210 215 220 Ala His Cys Arg Phe Thr Ala Leu Met Glu Gln Lys Ile Ala Glu Leu 225 230 235 240 Asp Lys Glu Val Ala Glu Arg Glu Ala Thr Gly Lys Val 245 250 10 289 PRT L. douglassi 10 Met Ala Lys Thr Arg Thr Ser Ser Leu Arg Asn Arg Arg Gln Leu Lys 1 5 10 15 Pro Ala Val Ala Ala Thr Ala Asp Asp Asp Lys Asp Gly Val Phe Met 20 25 30 Val Leu Leu Ser Cys Phe Lys Ile Phe Val Cys Phe Ala Phe Thr Val 35 40 45 Val Leu Ile Thr Ala Val Ala Trp Gly Leu Ile Met Val Leu Leu Leu 50 55 60 Pro Trp Pro Tyr Met Arg Ile Arg Leu Gly Asn Leu Tyr Gly His Ile 65 70 75 80 Ile Gly Gly Leu Val Ile Trp Ile Tyr Gly Ile Pro Ile Lys Ile Gln 85 90 95 Gly Ser Glu His Thr Lys Lys Arg Ala Ile Phe Thr Tyr Ile Ser Asn 100 105 110 His Ala Ser Pro Ile Asp Ala Phe Phe Val Met Trp Leu Ala Pro Ile 115 120 125 Gly Thr Val Gly Val Ala Lys Lys Glu Val Ile Trp Tyr Pro Leu Leu 130 135 140 Gly Gln Leu Tyr Thr Leu Ala His His Ile Arg Ile Asp Arg Ser Asn 145 150 155 160 Pro Ala Ala Ala Ile Gln Ser Phe Thr Met Lys Glu Ala Val Arg Val 165 170 175 Ile Thr Glu Lys Asn Leu Ser Leu Ile Met Phe Pro Glu Gly Thr Arg 180 185 190 Ser Gly Asp Gly Arg Leu Leu Pro Phe Lys Lys Gly Phe Val His Leu 195 200 205 Ala Leu Gln Ser His Leu Pro Ile Val Pro Met Ile Leu Thr Gly Thr 210 215 220 His Leu Ala Trp Phe Thr Arg Lys Gly Thr Phe Arg Val Arg Pro Val 225 230 235 240 Pro Ile Thr Val Lys Tyr Leu Pro Pro Ile Asn Thr Asp Asp Trp Thr 245 250 255 Val Asp Lys Ile Asp Asp Tyr Val Lys Met Ile His Asp Ile Tyr Val 260 265 270 Arg Asn Leu Pro Ala Ser Gln Lys Pro Leu Gly Ser Thr Asn Arg Ser 275 280 285 Lys 11 318 PRT C. nucifera 11 Met Asp Ala Ser Gly Ala Ser Ser Phe Leu Arg Gly Arg Cys Leu Glu 1 5 10 15 Ser Cys Phe Lys Ala Ser Phe Gly Met Ser Gln Pro Lys Asp Ala Ala 20 25 30 Gly Gln Pro Ser Arg Arg Pro Ala Asp Ala Asp Asp Phe Phe Thr Val 35 40 45 Asp Asp Asp Arg Trp Ile Thr Val Ile Leu Ser Val Val Arg Ile Ala 50 55 60 Ala Cys Phe Leu Ser Met Met Val Thr Thr Ile Val Trp Asn Met Ile 65 70 75 80 Met Leu Ile Leu Leu Pro Trp Pro Tyr Ala Arg Ile Arg Gln Gly Asn 85 90 95 Leu Tyr Gly His Val Thr Gly Arg Met Leu Phe Thr Met Trp Ile Leu 100 105 110 Gly Asn Pro Ile Thr Ile Glu Gly Ser Glu Phe Ser Asn Thr Arg Ala 115 120 125 Ile Tyr Ile Cys Asn His Ala Ser Leu Val Asp Ile Phe Leu Ile Met 130 135 140 Trp Leu Ile Pro Lys Gly Thr Val Thr Ile Ala Lys Lys Glu Ile Ile 145 150 155 160 Trp Tyr Pro Leu Phe Gly Gln Phe Thr Leu Tyr Val Leu Ala Asn His 165 170 175 Gln Arg Ile Asp Arg Ser Asn Pro Ser Ala Ala Ile Glu Ser Ile Lys 180 185 190 Glu Val Ala Arg Ala Val Val Lys Lys Asn Leu Ser Leu Ile Ile Phe 195 200 205 Pro Glu Gly Thr Arg Ser Lys Thr Gly Arg Leu Leu Pro Phe Lys Lys 210 215 220 Gly Phe Ile His Phe Thr Ile Ala Leu Gln Thr Arg Leu Pro Ile Val 225 230 235 240 Pro Met Val Leu Thr Gly Thr His Leu Ala Trp Arg Lys Asn Ser Leu 245 250 255 Arg Val Arg Pro Ala Pro Ile Thr Val Lys Tyr Phe Ser Pro Ile Lys 260 265 270 Thr Asp Asp Trp Glu Glu Glu Lys Ile Asn His Tyr Val Glu Met Ile 275 280 285 His Phe Thr Ala Leu Tyr Val Asp His Leu Pro Glu Ser Gln Lys Pro 290 295 300 Leu Val Ser Lys Gly Arg Asp Ala Ser Gly Arg Ser Asn Ser 305 310 315 12 1660 DNA Homo sapiens CDS (184)..(1311) 12 tctatgaaac caacatacat ggcgtttgca tcacagttgg agtcagatgt gagcccggag 60 ggcaggtgtc tggcttgtcc acccggaagc cctgagggca gctgttccca ctggctctgc 120 tgaccttgtg ccttggacgg ctgtcctcag cgaggggccg tgcacccgct cctgagcagc 180 gcc atg ggc ctg ctg gcc ttc ctg aag acc cag ttc gtg ctg cac ctg 228 Met Gly Leu Leu Ala Phe Leu Lys Thr Gln Phe Val Leu His Leu 1 5 10 15 ctg gtc ggc ttt gtc ttc gtg gtg agt ggt ctg gtc atc aac ttc gtc 276 Leu Val Gly Phe Val Phe Val Val Ser Gly Leu Val Ile Asn Phe Val 20 25 30 cag ctg tgc acg ctg gcg ctc tgg ccg gtc agc aag cag ctc tac cgc 324 Gln Leu Cys Thr Leu Ala Leu Trp Pro Val Ser Lys Gln Leu Tyr Arg 35 40 45 cgc ctc aac tgc cgc ctc gca tac tca ctc tgg agc caa ctg gtc atg 372 Arg Leu Asn Cys Arg Leu Ala Tyr Ser Leu Trp Ser Gln Leu Val Met 50 55 60 ctg ctg gag tgg tgg tcc tgc acg gag tgt aca ctg ttc acg gac cag 420 Leu Leu Glu Trp Trp Ser Cys Thr Glu Cys Thr Leu Phe Thr Asp Gln 65 70 75 gcc acg gta gag cgc ttt ggg aag gag cac gca gtc atc atc ctc aac 468 Ala Thr Val Glu Arg Phe Gly Lys Glu His Ala Val Ile Ile Leu Asn 80 85 90 95 cac aac ttc gag atc gac ttc ctc tgt ggg tgg acc atg tgt gag cgc 516 His Asn Phe Glu Ile Asp Phe Leu Cys Gly Trp Thr Met Cys Glu Arg 100 105 110 ttc gga gtg ctg ggg agc tcc aag gtc ctc gct aag aag gag ctg ctc 564 Phe Gly Val Leu Gly Ser Ser Lys Val Leu Ala Lys Lys Glu Leu Leu 115 120 125 tac gtg ccc ctc atc ggc tgg acg tgg tac ttt ctg gag att gtg ttc 612 Tyr Val Pro Leu Ile Gly Trp Thr Trp Tyr Phe Leu Glu Ile Val Phe 130 135 140 tgc aag cgg aag tgg gag gag gac cgg gac acc gtg gtc gaa ggg ctg 660 Cys Lys Arg Lys Trp Glu Glu Asp Arg Asp Thr Val Val Glu Gly Leu 145 150 155 agg cgc ctg tcg gac tac ccc gag tac atg tgg ttt ctc ctg tac tgc 708 Arg Arg Leu Ser Asp Tyr Pro Glu Tyr Met Trp Phe Leu Leu Tyr Cys 160 165 170 175 gag ggg acg cgc ttc acg gag acc aag cac cgc gtt agc atg gag gtg 756 Glu Gly Thr Arg Phe Thr Glu Thr Lys His Arg Val Ser Met Glu Val 180 185 190 gcg gct gct aag ggg ctt cct gtc ctc aag tac cac ctg ctg ccg cgg 804 Ala Ala Ala Lys Gly Leu Pro Val Leu Lys Tyr His Leu Leu Pro Arg 195 200 205 acc aag ggc ttc acc acc gca gtc aag tgc ctc cgg ggg aca gtc gca 852 Thr Lys Gly Phe Thr Thr Ala Val Lys Cys Leu Arg Gly Thr Val Ala 210 215 220 gct gtc tat gat gta acc ctg aac ttc aga gga aac aag aac ccg tcc 900 Ala Val Tyr Asp Val Thr Leu Asn Phe Arg Gly Asn Lys Asn Pro Ser 225 230 235 ctg ctg ggg atc ctc tac ggg aag aag tac gag gcg gac atg tgc gtg 948 Leu Leu Gly Ile Leu Tyr Gly Lys Lys Tyr Glu Ala Asp Met Cys Val 240 245 250 255 agg aga ttt cct ctg gaa gac atc ccg ctg gat gaa aag gaa gca gct 996 Arg Arg Phe Pro Leu Glu Asp Ile Pro Leu Asp Glu Lys Glu Ala Ala 260 265 270 cag tgg ctt cat aaa ctg tac cag gag aag gac gcg ctc cag gag ata 1044 Gln Trp Leu His Lys Leu Tyr Gln Glu Lys Asp Ala Leu Gln Glu Ile 275 280 285 tat aat cag aag ggc atg ttt cca ggg gag cag ttt aag cct gcc cgg 1092 Tyr Asn Gln Lys Gly Met Phe Pro Gly Glu Gln Phe Lys Pro Ala Arg 290 295 300 agg ccg tgg acc ctc ctg aac ttc ctg tcc tgg gcc acc att ctc ctg 1140 Arg Pro Trp Thr Leu Leu Asn Phe Leu Ser Trp Ala Thr Ile Leu Leu 305 310 315 tct ccc ctc ttc agt ttt gtc ttg ggc gtc ttt gcc agc gga tca cct 1188 Ser Pro Leu Phe Ser Phe Val Leu Gly Val Phe Ala Ser Gly Ser Pro 320 325 330 335 ctc ctg atc ctg act ttc ttg ggg ttt gtg gga gca gct tcc ttt gga 1236 Leu Leu Ile Leu Thr Phe Leu Gly Phe Val Gly Ala Ala Ser Phe Gly 340 345 350 gtt cgc aga ctg ata gga gta act gag ata gaa aaa ggc tcc agc tac 1284 Val Arg Arg Leu Ile Gly Val Thr Glu Ile Glu Lys Gly Ser Ser Tyr 355 360 365 gga aac caa gag ttt aag aaa aag gaa taattaatgg ctgtgactga 1331 Gly Asn Gln Glu Phe Lys Lys Lys Glu 370 375 acacacgcgg ccctgacggt ggtatccagt taactcaaaa ccaacacaca gagtgcagga 1391 aaagacaatt agaaactatt tttcttatta actggtgact aatattaaca aaacttgagc 1451 caagagtaaa gaattcagaa ggcctgtcag gtgaagtctt cagcctccca cagcgcaggg 1511 tcccagcatc tccacgcgcg cccgtgggag gtgggtccgg ccggagaggc ctcccgcgga 1571 cgccgtctct ccagaactcc gcttccaaga gggacctttg gctgctttct ctccttaaac 1631 ttagatcaaa ttttaaaaaa aaaaaaaaa 1660 13 376 PRT Homo sapiens 13 Met Gly Leu Leu Ala Phe Leu Lys Thr Gln Phe Val Leu His Leu Leu 1 5 10 15 Val Gly Phe Val Phe Val Val Ser Gly Leu Val Ile Asn Phe Val Gln 20 25 30 Leu Cys Thr Leu Ala Leu Trp Pro Val Ser Lys Gln Leu Tyr Arg Arg 35 40 45 Leu Asn Cys Arg Leu Ala Tyr Ser Leu Trp Ser Gln Leu Val Met Leu 50 55 60 Leu Glu Trp Trp Ser Cys Thr Glu Cys Thr Leu Phe Thr Asp Gln Ala 65 70 75 80 Thr Val Glu Arg Phe Gly Lys Glu His Ala Val Ile Ile Leu Asn His 85 90 95 Asn Phe Glu Ile Asp Phe Leu Cys Gly Trp Thr Met Cys Glu Arg Phe 100 105 110 Gly Val Leu Gly Ser Ser Lys Val Leu Ala Lys Lys Glu Leu Leu Tyr 115 120 125 Val Pro Leu Ile Gly Trp Thr Trp Tyr Phe Leu Glu Ile Val Phe Cys 130 135 140 Lys Arg Lys Trp Glu Glu Asp Arg Asp Thr Val Val Glu Gly Leu Arg 145 150 155 160 Arg Leu Ser Asp Tyr Pro Glu Tyr Met Trp Phe Leu Leu Tyr Cys Glu 165 170 175 Gly Thr Arg Phe Thr Glu Thr Lys His Arg Val Ser Met Glu Val Ala 180 185 190 Ala Ala Lys Gly Leu Pro Val Leu Lys Tyr His Leu Leu Pro Arg Thr 195 200 205 Lys Gly Phe Thr Thr Ala Val Lys Cys Leu Arg Gly Thr Val Ala Ala 210 215 220 Val Tyr Asp Val Thr Leu Asn Phe Arg Gly Asn Lys Asn Pro Ser Leu 225 230 235 240 Leu Gly Ile Leu Tyr Gly Lys Lys Tyr Glu Ala Asp Met Cys Val Arg 245 250 255 Arg Phe Pro Leu Glu Asp Ile Pro Leu Asp Glu Lys Glu Ala Ala Gln 260 265 270 Trp Leu His Lys Leu Tyr Gln Glu Lys Asp Ala Leu Gln Glu Ile Tyr 275 280 285 Asn Gln Lys Gly Met Phe Pro Gly Glu Gln Phe Lys Pro Ala Arg Arg 290 295 300 Pro Trp Thr Leu Leu Asn Phe Leu Ser Trp Ala Thr Ile Leu Leu Ser 305 310 315 320 Pro Leu Phe Ser Phe Val Leu Gly Val Phe Ala Ser Gly Ser Pro Leu 325 330 335 Leu Ile Leu Thr Phe Leu Gly Phe Val Gly Ala Ala Ser Phe Gly Val 340 345 350 Arg Arg Leu Ile Gly Val Thr Glu Ile Glu Lys Gly Ser Ser Tyr Gly 355 360 365 Asn Gln Glu Phe Lys Lys Lys Glu 370 375 14 1523 DNA Homo sapiens CDS (233)..(1174) 14 cacgctggcg ctctggccgg tcagcaagca gctctaccgc cgcctcaact gccgcctcgc 60 ctactcactc tggagcctag cacaaaacta gaagcaaccc aagcacctgt cactggagac 120 taattatgcg gcacccatac agggaccctc tgcggccatc atggagagcc ttcatcttgc 180 ccgtacagtt ttaagcgaaa aaggaagtat acaacaaagt ccataactgg tc atg ctg 238 Met Leu 1 ctg gag tgg tgg tcc tgc acg gag tgt aca ctg ttc acg gac cag gcc 286 Leu Glu Trp Trp Ser Cys Thr Glu Cys Thr Leu Phe Thr Asp Gln Ala 5 10 15 acg gta gag cgc ttt ggg aag gag cac gca gtc atc atc ctc aac cac 334 Thr Val Glu Arg Phe Gly Lys Glu His Ala Val Ile Ile Leu Asn His 20 25 30 aac ttc gag atc gac ttc ctc tgt ggg tgg acc atg tgt gag cgc ttc 382 Asn Phe Glu Ile Asp Phe Leu Cys Gly Trp Thr Met Cys Glu Arg Phe 35 40 45 50 gga gtg ctg ggg agc tcc aag gtc ctc gct aag aag gag ctg ctc tac 430 Gly Val Leu Gly Ser Ser Lys Val Leu Ala Lys Lys Glu Leu Leu Tyr 55 60 65 gtg ccc ctc atc ggc tgg acg tgg tac ttt ctg gag att gtg ttc tgc 478 Val Pro Leu Ile Gly Trp Thr Trp Tyr Phe Leu Glu Ile Val Phe Cys 70 75 80 aag cgg aag tgg gag gag gac cgg gac acc gtg gtc gaa ggg ctg agg 526 Lys Arg Lys Trp Glu Glu Asp Arg Asp Thr Val Val Glu Gly Leu Arg 85 90 95 cgc ctg tcg gac tac ccc gag tac atg tgg ttt ctc ctg tac tgc gag 574 Arg Leu Ser Asp Tyr Pro Glu Tyr Met Trp Phe Leu Leu Tyr Cys Glu 100 105 110 ggg acg cgc ttc acg gag acc aag cac cgc gtt agc atg gag gtg gcg 622 Gly Thr Arg Phe Thr Glu Thr Lys His Arg Val Ser Met Glu Val Ala 115 120 125 130 gct gct aag ggg ctt cct gtc ctc aag tac cac ctg ctg ccg cgg acc 670 Ala Ala Lys Gly Leu Pro Val Leu Lys Tyr His Leu Leu Pro Arg Thr 135 140 145 aag ggc ttc acc acc gca gtc aag tgc ctc cgg ggg aca gtc gca gct 718 Lys Gly Phe Thr Thr Ala Val Lys Cys Leu Arg Gly Thr Val Ala Ala 150 155 160 gtc tat gat gta acc ctg aac ttc aga gga aac aag aac ccg tcc ctg 766 Val Tyr Asp Val Thr Leu Asn Phe Arg Gly Asn Lys Asn Pro Ser Leu 165 170 175 ctg ggg atc ctc tac ggg aag aag tac gag gcg gac atg tgc gtg agg 814 Leu Gly Ile Leu Tyr Gly Lys Lys Tyr Glu Ala Asp Met Cys Val Arg 180 185 190 aga ttt cct ctg gaa gac atc ccg ctg gat gaa aag gaa gca gct cag 862 Arg Phe Pro Leu Glu Asp Ile Pro Leu Asp Glu Lys Glu Ala Ala Gln 195 200 205 210 tgg ctt cat aaa ctg tac cag gag aag gac gcg ctc cag gag ata tat 910 Trp Leu His Lys Leu Tyr Gln Glu Lys Asp Ala Leu Gln Glu Ile Tyr 215 220 225 aat cag aag ggc atg ttt cca ggg gag cag ttt aag cct gcc cgg agg 958 Asn Gln Lys Gly Met Phe Pro Gly Glu Gln Phe Lys Pro Ala Arg Arg 230 235 240 ccg tgg acc ctc ctg aac ttc ctg tcc tgg gcc acc att ctc ctg tct 1006 Pro Trp Thr Leu Leu Asn Phe Leu Ser Trp Ala Thr Ile Leu Leu Ser 245 250 255 ccc ctc ttc agt ttt gtc ttg ggc gtc ttt gcc agc gga tca cct ctc 1054 Pro Leu Phe Ser Phe Val Leu Gly Val Phe Ala Ser Gly Ser Pro Leu 260 265 270 ctg atc ctg act ttc ttg ggg ttt gtg gga gca gct tcc ttt gga gtt 1102 Leu Ile Leu Thr Phe Leu Gly Phe Val Gly Ala Ala Ser Phe Gly Val 275 280 285 290 cgc aga ctg ata gga gta act gag ata gaa aaa ggc tcc agc tac gga 1150 Arg Arg Leu Ile Gly Val Thr Glu Ile Glu Lys Gly Ser Ser Tyr Gly 295 300 305 aac caa gag ttt aag aaa aag gaa taattaatgg ctgtgactga acacacgcgg 1204 Asn Gln Glu Phe Lys Lys Lys Glu 310 ccctgacggt ggtatccagt taactcaaaa ccaacacaca gagtgcagga aaagacaatt 1264 agaaactatt tttcttatta actggtgact aatattaaca aaacttgagc caagagtaaa 1324 gaattcagaa ggcctgtcag gtgaagtctt cagcctccca cagcgcaggg tcccagcatc 1384 tccacgcgcg cccgtgggag gtgggtccgg ccggagaggc ctcccgcgga cgccgtctct 1444 ccagaactcc gcttccaaga gggacctttg gctgctttct ctccttaaac ttagatcaaa 1504 ttttaaaaaa aaaaaaaaa 1523 15 314 PRT Homo sapiens 15 Met Leu Leu Glu Trp Trp Ser Cys Thr Glu Cys Thr Leu Phe Thr Asp 1 5 10 15 Gln Ala Thr Val Glu Arg Phe Gly Lys Glu His Ala Val Ile Ile Leu 20 25 30 Asn His Asn Phe Glu Ile Asp Phe Leu Cys Gly Trp Thr Met Cys Glu 35 40 45 Arg Phe Gly Val Leu Gly Ser Ser Lys Val Leu Ala Lys Lys Glu Leu 50 55 60 Leu Tyr Val Pro Leu Ile Gly Trp Thr Trp Tyr Phe Leu Glu Ile Val 65 70 75 80 Phe Cys Lys Arg Lys Trp Glu Glu Asp Arg Asp Thr Val Val Glu Gly 85 90 95 Leu Arg Arg Leu Ser Asp Tyr Pro Glu Tyr Met Trp Phe Leu Leu Tyr 100 105 110 Cys Glu Gly Thr Arg Phe Thr Glu Thr Lys His Arg Val Ser Met Glu 115 120 125 Val Ala Ala Ala Lys Gly Leu Pro Val Leu Lys Tyr His Leu Leu Pro 130 135 140 Arg Thr Lys Gly Phe Thr Thr Ala Val Lys Cys Leu Arg Gly Thr Val 145 150 155 160 Ala Ala Val Tyr Asp Val Thr Leu Asn Phe Arg Gly Asn Lys Asn Pro 165 170 175 Ser Leu Leu Gly Ile Leu Tyr Gly Lys Lys Tyr Glu Ala Asp Met Cys 180 185 190 Val Arg Arg Phe Pro Leu Glu Asp Ile Pro Leu Asp Glu Lys Glu Ala 195 200 205 Ala Gln Trp Leu His Lys Leu Tyr Gln Glu Lys Asp Ala Leu Gln Glu 210 215 220 Ile Tyr Asn Gln Lys Gly Met Phe Pro Gly Glu Gln Phe Lys Pro Ala 225 230 235 240 Arg Arg Pro Trp Thr Leu Leu Asn Phe Leu Ser Trp Ala Thr Ile Leu 245 250 255 Leu Ser Pro Leu Phe Ser Phe Val Leu Gly Val Phe Ala Ser Gly Ser 260 265 270 Pro Leu Leu Ile Leu Thr Phe Leu Gly Phe Val Gly Ala Ala Ser Phe 275 280 285 Gly Val Arg Arg Leu Ile Gly Val Thr Glu Ile Glu Lys Gly Ser Ser 290 295 300 Tyr Gly Asn Gln Glu Phe Lys Lys Lys Glu 305 310 16 1774 DNA Homo sapiens CDS (158)..(1291) 16 tgaacccagc cggctccatc tcagcttctg gtttctaagt ccatgtgcca aaggctgcca 60 ggaaggagac gccttcctga gtcctggatc tttcttcctt ctggaaatct ttgactgtgg 120 gtagttattt atttctgaat aagagcgtcc acgcatc atg gac ctc gcg gga ctg 175 Met Asp Leu Ala Gly Leu 1 5 ctg aag tct cag ttc ctg tgc cac ctg gtc ttc tgc tac gtc ttt att 223 Leu Lys Ser Gln Phe Leu Cys His Leu Val Phe Cys Tyr Val Phe Ile 10 15 20 gcc tca ggg cta atc atc aac acc att cag ctc ttc act ctc ctc ctc 271 Ala Ser Gly Leu Ile Ile Asn Thr Ile Gln Leu Phe Thr Leu Leu Leu 25 30 35 tgg ccc att aac aag cag ctc ttc cgg aag atc aac tgc aga ctg tcc 319 Trp Pro Ile Asn Lys Gln Leu Phe Arg Lys Ile Asn Cys Arg Leu Ser 40 45 50 tat tgc atc tca agc cag ctg gtg atg ctg ctg gag tgg tgg tcg ggc 367 Tyr Cys Ile Ser Ser Gln Leu Val Met Leu Leu Glu Trp Trp Ser Gly 55 60 65 70 acg gaa tgc acc atc ttc acg gac ccg cgc gcc tac ctc aag tat ggg 415 Thr Glu Cys Thr Ile Phe Thr Asp Pro Arg Ala Tyr Leu Lys Tyr Gly 75 80 85 aag gaa aat gcc atc gtg gtt ctc aac cac aag ttt gaa att gac ttt 463 Lys Glu Asn Ala Ile Val Val Leu Asn His Lys Phe Glu Ile Asp Phe 90 95 100 ctg tgt ggc tgg agc ctg tcc gaa cgc ttt ggg ctg tta ggg ggc tcc 511 Leu Cys Gly Trp Ser Leu Ser Glu Arg Phe Gly Leu Leu Gly Gly Ser 105 110 115 aag gtc ctg gcc aag aaa gag ctg gcc tat gtc cca att atc ggc tgg 559 Lys Val Leu Ala Lys Lys Glu Leu Ala Tyr Val Pro Ile Ile Gly Trp 120 125 130 atg tgg tac ttc acc gag atg gtc ttc tgt tcg cgc aag tgg gag cag 607 Met Trp Tyr Phe Thr Glu Met Val Phe Cys Ser Arg Lys Trp Glu Gln 135 140 145 150 gat cgc aag acg gtt gcc acc agt ttg cag cac ctc cgg gac tac ccc 655 Asp Arg Lys Thr Val Ala Thr Ser Leu Gln His Leu Arg Asp Tyr Pro 155 160 165 gag aag tat ttt ttc ctg att cac tgt gag ggc aca cgg ttc acg gag 703 Glu Lys Tyr Phe Phe Leu Ile His Cys Glu Gly Thr Arg Phe Thr Glu 170 175 180 aag aag cat gag atc agc atg cag gtg gcc cgg gcc aag ggg ctg cct 751 Lys Lys His Glu Ile Ser Met Gln Val Ala Arg Ala Lys Gly Leu Pro 185 190 195 cgc ctc aag cat cac ctg ttg cca cga acc aag ggc ttc gcc atc acc 799 Arg Leu Lys His His Leu Leu Pro Arg Thr Lys Gly Phe Ala Ile Thr 200 205 210 gtg agg agc ttg aga aat gta gtt tca gct gta tat gac tgt aca ctc 847 Val Arg Ser Leu Arg Asn Val Val Ser Ala Val Tyr Asp Cys Thr Leu 215 220 225 230 aat ttc aga aat aat gaa aat cca aca ctg ctg gga gtc cta aac gga 895 Asn Phe Arg Asn Asn Glu Asn Pro Thr Leu Leu Gly Val Leu Asn Gly 235 240 245 aag aaa tac cat gca gat ttg tat gtt agg agg atc cca ctg gaa gac 943 Lys Lys Tyr His Ala Asp Leu Tyr Val Arg Arg Ile Pro Leu Glu Asp 250 255 260 atc cct gaa gac gat gac gag tgc tcg gcc tgg ctg cac aag ctc tac 991 Ile Pro Glu Asp Asp Asp Glu Cys Ser Ala Trp Leu His Lys Leu Tyr 265 270 275 cag gag aag gat gcc ttt cag gag gag tac tac agg acg ggc acc ttc 1039 Gln Glu Lys Asp Ala Phe Gln Glu Glu Tyr Tyr Arg Thr Gly Thr Phe 280 285 290 cca gag acg ccc atg gtg ccc ccc cgg cgg ccc tgg acc ctc gtg aac 1087 Pro Glu Thr Pro Met Val Pro Pro Arg Arg Pro Trp Thr Leu Val Asn 295 300 305 310 tgg ctg ttt tgg gcc tcg ctg gtg ctc tac cct ttc ttc cag ttc ctg 1135 Trp Leu Phe Trp Ala Ser Leu Val Leu Tyr Pro Phe Phe Gln Phe Leu 315 320 325 gtc agc atg atc agg agc ggg tct tcc ctg acg ctg gcc agc ttc atc 1183 Val Ser Met Ile Arg Ser Gly Ser Ser Leu Thr Leu Ala Ser Phe Ile 330 335 340 ctc gtc ttc ttt gtg gcc tcc gtg gga gtt cga tgg atg att ggt gtg 1231 Leu Val Phe Phe Val Ala Ser Val Gly Val Arg Trp Met Ile Gly Val 345 350 355 acg gaa att gac aag ggc tct gcc tac ggc aac tct gac agc aag cag 1279 Thr Glu Ile Asp Lys Gly Ser Ala Tyr Gly Asn Ser Asp Ser Lys Gln 360 365 370 aaa ctg aat gac tgactcaggg aggtgtcacc atccgaaggg aaccttgggg 1331 Lys Leu Asn Asp 375 aactggtggc ctctgcatat cctccttagt gggacacggt gacaaaggct gggtgagccc 1391 ctgctgggca cggcggaagt cacgacctct ccagccaggg agtctggtct caaggccgga 1451 tggggaggaa gatgttttgt aatctttttt tccccatgtg ctttagtggg ctttggtttt 1511 ctttttgtgc gagtgtgtgt gagaatggct gtgtggtgag tgtgaacttt gttctgtgat 1571 catagaaagg gtattttagg ctgcagggga gggcagggct ggggaccgaa ggggacaagt 1631 tcccctttca tcctttggtg ctgagttttc tgtaaccctt ggttgccaga gataaagtga 1691 aaagtgcttt aggtgagatg actaaattat gcctccaaga aaaaaaaatt aaagtgcttt 1751 tctgggtcaa aaaaaaaaaa aaa 1774 17 378 PRT Homo sapiens 17 Met Asp Leu Ala Gly Leu Leu Lys Ser Gln Phe Leu Cys His Leu Val 1 5 10 15 Phe Cys Tyr Val Phe Ile Ala Ser Gly Leu Ile Ile Asn Thr Ile Gln 20 25 30 Leu Phe Thr Leu Leu Leu Trp Pro Ile Asn Lys Gln Leu Phe Arg Lys 35 40 45 Ile Asn Cys Arg Leu Ser Tyr Cys Ile Ser Ser Gln Leu Val Met Leu 50 55 60 Leu Glu Trp Trp Ser Gly Thr Glu Cys Thr Ile Phe Thr Asp Pro Arg 65 70 75 80 Ala Tyr Leu Lys Tyr Gly Lys Glu Asn Ala Ile Val Val Leu Asn His 85 90 95 Lys Phe Glu Ile Asp Phe Leu Cys Gly Trp Ser Leu Ser Glu Arg Phe 100 105 110 Gly Leu Leu Gly Gly Ser Lys Val Leu Ala Lys Lys Glu Leu Ala Tyr 115 120 125 Val Pro Ile Ile Gly Trp Met Trp Tyr Phe Thr Glu Met Val Phe Cys 130 135 140 Ser Arg Lys Trp Glu Gln Asp Arg Lys Thr Val Ala Thr Ser Leu Gln 145 150 155 160 His Leu Arg Asp Tyr Pro Glu Lys Tyr Phe Phe Leu Ile His Cys Glu 165 170 175 Gly Thr Arg Phe Thr Glu Lys Lys His Glu Ile Ser Met Gln Val Ala 180 185 190 Arg Ala Lys Gly Leu Pro Arg Leu Lys His His Leu Leu Pro Arg Thr 195 200 205 Lys Gly Phe Ala Ile Thr Val Arg Ser Leu Arg Asn Val Val Ser Ala 210 215 220 Val Tyr Asp Cys Thr Leu Asn Phe Arg Asn Asn Glu Asn Pro Thr Leu 225 230 235 240 Leu Gly Val Leu Asn Gly Lys Lys Tyr His Ala Asp Leu Tyr Val Arg 245 250 255 Arg Ile Pro Leu Glu Asp Ile Pro Glu Asp Asp Asp Glu Cys Ser Ala 260 265 270 Trp Leu His Lys Leu Tyr Gln Glu Lys Asp Ala Phe Gln Glu Glu Tyr 275 280 285 Tyr Arg Thr Gly Thr Phe Pro Glu Thr Pro Met Val Pro Pro Arg Arg 290 295 300 Pro Trp Thr Leu Val Asn Trp Leu Phe Trp Ala Ser Leu Val Leu Tyr 305 310 315 320 Pro Phe Phe Gln Phe Leu Val Ser Met Ile Arg Ser Gly Ser Ser Leu 325 330 335 Thr Leu Ala Ser Phe Ile Leu Val Phe Phe Val Ala Ser Val Gly Val 340 345 350 Arg Trp Met Ile Gly Val Thr Glu Ile Asp Lys Gly Ser Ala Tyr Gly 355 360 365 Asn Ser Asp Ser Lys Gln Lys Leu Asn Asp 370 375 18 52 PRT Yeast 18 Pro Phe Lys Lys Gly Ala Phe His Leu Ala Gln Gln Gly Lys Ile Pro 1 5 10 15 Ile Val Pro Val Val Val Ser Asn Thr Ser Thr Leu Val Ser Pro Lys 20 25 30 Tyr Gly Val Phe Asn Arg Gly Cys Met Ile Val Arg Ile Leu Lys Pro 35 40 45 Ile Ser Thr Glu 50 19 52 PRT Homo sapiens 19 Pro Ser Asn Cys Gly Ala Phe His Leu Ala Val Gln Ala Gln Val Pro 1 5 10 15 Ile Val Pro Ile Val Met Ser Ser Tyr Gln Asp Phe Tyr Cys Lys Lys 20 25 30 Glu Arg Arg Phe Thr Ser Gly Gln Cys Gln Val Arg Val Leu Pro Pro 35 40 45 Val Pro Thr Glu 50 20 18 DNA Artificial Sequence Description of Artificial Sequence synthetic oligonucleotide 20 tgcaagatgg aaggcgcc 18 21 6 PRT Homo sapiens 21 Gly Ala Phe His Leu Ala 1 5 22 60 PRT Yeast 22 Gln Gln Gly Lys Ile Pro Ile Val Pro Val Val Val Ser Asn Thr Ser 1 5 10 15 Thr Leu Val Ser Pro Lys Tyr Gly Val Phe Asn Arg Gly Cys Met Ile 20 25 30 Val Arg Ile Leu Lys Pro Ile Ser Thr Glu Asn Leu Thr Lys Asp Lys 35 40 45 Ile Gly Glu Phe Ala Glu Lys Val Arg Asp Gln Met 50 55 60 23 60 PRT Homo sapiens 23 Val Arg Glu Asn Val Pro Ile Val Pro Val Val Tyr Ser Ser Phe Ser 1 5 10 15 Ser Phe Tyr Asn Thr Lys Lys Lys Phe Phe Thr Ser Gly Thr Val Thr 20 25 30 Val Gln Val Leu Glu Ala Ile Pro Thr Ser Gly Leu Thr Ala Ala Asp 35 40 45 Val Pro Ala Leu Arg Gly Thr Pro Ala Thr Gly Pro 50 55 60 24 20 DNA Artificial Sequence Description of Artificial Sequence synthetic oligonucleotide 24 cctcaaagtg tggatctatc 20 25 21 DNA Artificial Sequence Description of Artificial Sequence synthetic oligonucleotide 25 ggaagagtac accacgggga c 21 26 21 DNA Artificial Sequence Description of Artificial Sequence primer 26 gactctagcc taggcttttg c 21 27 21 DNA Artificial Sequence Description of Artificial Sequence primer 27 ctagcttata atacgactca c 21 28 23 PRT Maize 28 Gly Leu Gln Arg Leu Lys Asp Phe Pro Arg Pro Phe Trp Leu Ala Leu 1 5 10 15 Phe Val Glu Gly Thr Arg Phe 20 29 23 PRT Homo sapiens 29 Gly Leu Arg Arg Leu Ser Asp Tyr Pro Glu Tyr Met Trp Phe Leu Leu 1 5 10 15 Tyr Cys Glu Gly Thr Arg Phe 20 30 27 DNA Artificial Sequence Description of Artificial Sequence synthetic oligonucleotide 30 gactaccccg agtacatgtg gtttctc 27 31 9 PRT Homo sapiens 31 Asp Tyr Pro Glu Tyr Met Trp Phe Leu 1 5 32 24 DNA Artificial Sequence Description of Artificial Sequence synthetic oligonucleotide 32 cacatgtccg cctcgtactt cttc 24 33 46 PRT Homo sapiens 33 Met Gly Leu Leu Ala Phe Leu Lys Thr Gln Phe Val Leu His Leu Leu 1 5 10 15 Val Gly Phe Val Phe Val Val Ser Gly Leu Val Ile Asn Phe Val Gln 20 25 30 Leu Cys Thr Leu Ala Leu Trp Pro Val Ser Lys Gln Leu Tyr 35 40 45 34 46 PRT Homo sapiens 34 Met Asp Leu Ala Gly Leu Leu Lys Ser Gln Phe Leu Cys His Leu Val 1 5 10 15 Phe Cys Tyr Val Phe Ile Ala Ser Gly Leu Ile Ile Asn Thr Ile Gln 20 25 30 Leu Phe Thr Leu Leu Leu Trp Pro Ile Asn Lys Gln Leu Phe 35 40 45 35 29 DNA Artificial Sequence Description of Artificial Sequence primer 35 ggctctagat attaatagta atcaattac 29 36 26 DNA Artificial Sequence Description of Artificial Sequence primer 36 cctcacgcat gcaccatggt aatagc 26 37 24 DNA Artificial Sequence Description of Artificial Sequence primer 37 ggtgcatgcg tgaggctccg gtgc 24 38 28 DNA Artificial Sequence Description of Artificial Sequence primer 38 gtagttttca cggtacctga aatggaag 28 39 30 DNA Artificial Sequence Description of Artificial Sequence primer 39 ggcccggtac catgggcctg ctggccttcc 30 40 33 DNA Artificial Sequence Description of Artificial Sequence primer 40 taactcctcg agttattcct ttttcttaaa ctc 33 41 35 DNA Artificial Sequence Description of Artificial Sequence primer 41 atggtggtac caccatggac ctcgcgggac tgctg 35 42 26 DNA Artificial Sequence Description of Artificial Sequence primer 42 ggaggatatc tagaggccac cagttc 26 

We claim:
 1. An isolated polynucleotide encoding a polypeptide having Lysophosphatidic Acid Acyltransferase (LPAAT) activity, comprising a nucleotide sequence selected from the group consisting of: (a) the DNA sequence of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof; and (b) a DNA sequence which encodes the polypeptide of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof.
 2. An isolated polypeptide having LPAAT activity, comprising the amino acid sequence of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof.
 3. A method for screening one or more compounds to determine whether said one or more compounds increases or decreases LPAAT activity, comprising: (a) contacting the polypeptide of claim 2 with one or more substrates for said polypeptide and with said one or more compounds; and (b) measuring whether the LPAAT activity of said polypeptide is increased or decreased by said one or more compounds.
 4. The method of claim 3, wherein said one or more compounds is selected from a combinatorial chemical library.
 5. A method of expressing the polypeptide of claim 2, comprising: (a) introducing into a cell a polynucleotide comprising a nucleotide sequence selected from the group consisting of: (i) the DNA sequence of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof; and (ii) a DNA sequence which encodes the polypeptide of FIG. 9, FIG. 10, or FIG. 11 and biologically active fragments thereof, wherein said polynucleotide is operably linked to a promoter; and (b) maintaining or growing said cell under conditions that result in the expression of said polypeptide.
 6. The isolated polynucleotide of claim 1, wherein said polynucleotide comprises the DNA sequence of FIG. 9 or a DNA sequence encoding the polypeptide of FIG.
 9. 7. The isolated polynucleotide of claim 1, wherein said polynucleotide comprises the DNA sequence of FIG. 10 or a DNA sequence encoding the polypeptide of FIG.
 10. 8. The isolated polynucleotide of claim 1, wherein said polynucleotide comprises the DNA sequence of FIG. 11 or a DNA sequence encoding the polypeptide of FIG.
 11. 9. The isolated polypeptide of claim 2, wherein said polypeptide comprises the amino acid sequence of FIG.
 9. 10. The isolated polypeptide of claim 2, wherein said polypeptide comprises the amino acid sequence of FIG.
 10. 11. The isolated polypeptide of claim 2, wherein said polypeptide comprises the amino acid sequence of FIG.
 11. 12. An isolated polynucleotide encoding a polypeptide having Lysophosphatidic Acid Acyltransferase (LPAAT) activity, comprising a DNA sequence capable of hybridizing under high stringency conditions to the complement of (a) or (b) of claim 1 and which encodes a polypeptide having LPAAT activity.
 13. A method of expressing a polypeptide having LPAAT activity, comprising: (a) introducing into a cell a polynucleotide comprising a DNA sequence capable of hybridizing under high stringency conditions to the complement of (a) or (b) of claim 1 and which encodes a polypeptide having LPAAT activity, wherein said polynucleotide is operably linked to a promoter, and (b) maintaining or growing said cell under conditions that result in the expression of said polypeptide. 